My personal perspective
I like this instrument, and I would like to have it. However, I have enough current projects to occupy my time, and if I did get this one it would just further dilute my resources. So I've decided to be sensible for a change and not compete with the rest of you for this instrument, so that hopefully it will be bought by someone who will put a dedicated effort into making music on it.
My purpose in presenting these observations is that I hope the additional information will help both the seller and potential buyers to settle on a fair price.
In retrospect, my examination of the instrument wasn't as methodical as it should have been, but this was in part because I was impressed by its general condition and playability. (And I was rather tired from a hectic cross-country odyssey.) Also, for unknown reasons a number of the photos I took turned out to be too blurred to be useful, and a few I thought I took seem to be missing. My apologies to all concerned.
The instrument has 50 buttons, plus an air button which isn't counted in the 50.
It has a 6-fold black bellows (no bellows papers), with gold embossing on the ends.
The ends are metal, I presume nickel-plated. The buttons are also metal.
The palm supports are not wood, but metal. This is a feature I've seen before on some Jeffries instruments. I personally like it. The straps are clearly not original, but I find them to be excellent.
It has the C. Jeffries name both stamped into the left-hand end and engraved in the oval on the right-hand end. The oval contains the name, but no address. (My "detail" picture of that oval turned out so blurred that nothing could be made out, and even the picture of the entire end is blurred. I'm very sorry for that.) The Aldershot Road address stamped into the edge of the right-hand end. (This detail photo came out nice and clear. I wish all the others had.)
The instrument was apparently worked on more than once in its history, since it has stamps from both H. Crabb & Son and R. Whitten. It also has the pencilled notation, "The maker is C. Jeffries," but I have no idea whether that was put there by Crabb, Whitten, or someone else.
I would describe this instrument as being in "good" condition. It has a couple of problems (detailed below) that I consider minor and easily repairable. If these are corrected, I would consider it a playable instrument. In fact, by ignoring these problems I was able to play a tune on the instrument without difficulty.
The reeds in particular seem to be in very good shape, in need of little or no adjustment.
The action (of which I unfortunately don't have a picture, but which I did look at) is not shiny clean, but neither is it in need of major cleaning. More to the point, it works well and seems uniformly responsive.
One of the end bolts was too short to hold the end, and I presume it wasn't original kit. I replaced it with a spare Wheatstone bolt I had with me, but left the too-short one with the instrument.
Reeds, pitch, and tuning
As can be seen in the photos, the reeds are steel, clean, and in good condition. Furthermore, they all appeaer to have undergone significant non-original filing. This causes me to speculate that the instrument was originally in Bb but was at some point retuned to C, its current key.
I didn't have any fancy electronics with me, but I did have a Dipper County Clare anglo. This Jeffries appeared to be in good tune with both itself and the County Clare. From this I conclude that it is now not only in the key of C, but equal-tempered and tuned to A440.
One reed (Eb in the right hand) was choking and couldn't be cured just by gentle adjustment. It looked like it might have a tiny bit of corrosion, but I couldn't be absolutely sure in the light available. I tried gently inserting a razor blade between the sides of the reed and the reed frame, to knock loose any crystals of corrosion, and that seemed to do the trick.
There is a hole in one bellows corner and some wear on other corners along the same edge. With apologies to all (Alan, the seller, as well as potential buyers), the bellows appears more worn in my photo than what I noticed while I was looking at it. I believe this is because that is the edge which is underneath the instrument while it's being played, so most of the time it wasn't visible, and I didn't examine it as carefully as I should have. (I almost didn't notice the hole at all, which was careless on my part.) Preventive cover patches should be adequate to prevent more holes, unless you let the bellows hang over your leg while playing. (See further comments below.) The other bellows edges looked in good condition, and I didn't feel that leakage hindered my playing, in spite of the one obvious hole.
One pad is not seating properly, so the note sounds constantly with any reasonable pressure. I tried adjusting this, but my simple efforts weren't adequate. I'm not sure whether remounting the pad would be enough, or whether a new pad is necessary, or possibly even a new spring. I don't think the spring is the problem (it didn't seem weak, nor look damaged in any way), but I can't be absolutely sure.
In addition to the unwanted "drone", there is an additional high-pitched squeal. This may in fact be a secondary effect of the note with the leaking pad, since I was unable to isolate it, but I can't be sure.
More on condition
The above are the only significant "problems" I noticed. They strike me as easily fixed by any competent professional. When these are fixed I would consider the instrument to be quite playable. The pads are old, but seem generally to be seating well. I tried playing the instrument and found the action and response to be even and good.
If I were buying this instrument, I would have the bellows hole patched and a bit of protective skiver placed over the worn parts. If I were short on money I would have the leaking pad fixed and whatever adjustment is needed to fix the "squeal", and I think I would find it comfortably playable. Eventually (right away, if I felt flush) I would have it fitted with all new pads and valves, as the ones which are there are old, though seemingly adequate. I don't think that a new bellows is necessary, but that patching the bellows should be adequate for many years to come.
What about price?
I don't consider myself qualified to say anything definite about price, except that it should be considerably less than a Jeffries anglo in comparable condition. The reason is that there just aren't enough players -- or would-be players -- of the Jeffries duet system to push the price up.
One hears about Jeffries duets being converted to anglos, but that would in fact be a major undertaking. Simply shifting the reeds around would undoubtedly require fitting many reed frames into slots of the wrong size, so that it must be easier to build completely new reed pans... and that is not easy. Furthermore, it's the Irish market that's driving anglo prices, but most "Irish" players would consider a 50-button instrument unreasonably heavy. What about the alternative of just taking some of the reeds from a Jeffries duet and building a new instrument around it? I hear it's been done, but once again one would have to factor out the cost of building the new instrument, plus the fact that while it would have Jeffries reeds, it wouldn't actually be "a Jeffries".
Thus one can't expect a Jeffries duet to command the same price as a Jeffries anglo simply because it's comparable in other respects to the anglo. Even if someone were to buy it for "conversion", to make that worthwhile they would have reduce what they would pay at least by the cost of the conversion.
Personally, I dearly hope this instrument goes to someone who will play it as what it is, not to a "butcher".
For this instrument, I would think £1500 would be too high a price and £500 too low, but I won't commit myself to anything more precise than that. If anyone else wants to be more daring, they could post their opinion on concertina.net.
Notes on the individual photos:
Upper left - side view with bellows extended
Unfortunately very blurred, but at least you can see the number of
folds, the lack of decorative papers, and the presence of the gold embossing.
Upper center - bellows detail showing the holed corner
Fine detail. No further comment.
Upper right - R.H. end detail showing stamped Aldershot Rd. address
Fine detail. No further comment.
2nd row left - R.H. end
Unfortunately blurred, thus obscuring the Jeffries name in the oval.
2nd row center - L.H. end
Clear. The C. Jeffries name is stamped faintly into this end.
2nd row right - R.H. end
Clear. This is the underside of the R.H. action board, showing the pads. (As noted above, I'm sorry that I don't have a photo of the action itself.)
Bottom left - R.H. reed pan in bellows end
Here you can clearly see the condition of the reeds.
Bottom center - R.H. reed pan "under side"
Again you can clearly see the condition of the reeds.
Bottom right - through the bellows to the L.H. end
Here you can clearly see the condition of the bellows from the inside. Also a few of the reeds in the L.H. end.