Richard Mellish

That seems very plausible, and might explain the Xs against some of pad holes. It would be helpful for the OP to post pictures of the reeds, both to show their condition and possibly to reveal their original pitches. I hope this instrument finds a home with someone on here who can give us a full report on its condition and, preferably, get all the notes restored to the usual Wheatstone ones. As I said, I am half tempted to buy it myself. However I do already have a Wheatstone (Dickinson) G/D which has served me very well for nearly 40 years ...

As the owner of two variants on Wheatstone 40-key layout I could contribute those, but how do I do that?

I encountered it for the first time only a year or three ago, and I don't think I'd seen that name for it until now. I wasn't aware of it when I specified some changes from standard Wheatstone on two concertinas that were built to my specifications.

The "Wheatstone (ish!) layout" description is spot-on. The extra buttons beyond the standard 30 are in the same positions as standard Wheatstone, but the two D4s in the same direction on the LH end and the two D#5s in the same direction on the RH end seem a very strange waste of buttons unless someone had a strong wish to use particular fingerings. Possibly it was built as a special or someone had these notes changed for their particular requirements, or perhaps some reeds have drifted badly. But some notes seem much too different to have drifted so far, e.g. on the RH end, middle row, first button push D#5 instead of C5, and G#6 instead of A4. If I were to buy it (which I am half tempted to do) I would certainly want it re-tuned and/or reeds replaced as necessary to convert it back to standard. Questions for the OP. How did you identify the notes? Were they close to those you have marked or were some of them many cents out? If it is to be shipped to the UK or Europe, import tax is likely to be a much bigger deal than the cost of shipping.

While we're being pedantic about terminology, it's perhaps worth pointing out that what the OP called "an old English style font" is a style that was normal for most purposes in Germany until around the time of WWII, well after it went out of fashion in most other places.

I'm wondering whether the OP forgot to include a smiley.

Irrespective of the ease or difficulty of the transition to a different system, might the load on your thumbs be a problem if you already have some arthritis?

If someone wishes to sell a concertina, by all means advertise it on Facebook or anywhere else but why not on here too?

I have no connection with this, but it was mentioned on the Anglo Wizard thread and seems worth a mention here. https://detroit.craigslist.org/mcb/msg/d/washington-40-button-anglo-concertina/7655943887.html It could be useful for someone to see how they get on with the extra buttons without spending much money.

I had clear priorities when playing for morris. Top priority: play loud enough to be heard above the sound of the dancers' clogs and sticks and general street noise. (Rationale: if they can't hear you, you might as well not be playing at all.) Middle priority: keep the rhythm. Bottom priority: play the right notes.

That chart is mind-boggling, with all those different chords just for A. I have been playing for over 50 years and have never felt the need for very many chords. When I was a child my grandfather showed me a few chords on the piano, which I now recognise as what guitarists call the "three chord trick". Those are essentially what I use on the Anglo, though usually not all the possible notes of a chord at the same time. A one-row melodion has just two chords, one on pull and one on push, and those serve well enough. I'm not saying no-one ever needs some of those chords, but I think I am saying Walk before you run.

Are you able to visit somewhere where you can try out various concertinas - either a dealer or a meeting of players?

Clarification: "accordion" to me implies piano accordion or 3- or 5-row chromatic. What some call a diatonic accordion I think of as a melodion. If an accordion repairer deals with the latter, then a reed plate with different notes should be no problem.

A spare accordion reed block will have both reeds tuned to the same note, so you will need to explain to the repairer that you need two different notes.

Fair enough, but still the first I'd heard of it, and no good for those of us who decline to register on Facebook.