I have been following this forum discussion with interest although I don't have it in front of me as I write. Someone wrote to the effect that for Irish music it 'has to be an Anglo'. I would go further and say that for traditional music it has to be an Anglo. I can think of no examples of the English system in Irish music before 'the revival' while the Anglo is fundamental and omnipresent. In England where the evidence for the Anglo is pretty thin the evidence for the English is thinner still. I can recall one picture of a trio, cello and two English concertinas, which was, I think, on the cover of the Boscastle Breakdown LP, but I can recall no other evidence.
Let me make it very clear that I am not belittling the English system; there are some great exponents of it - the Gordon Cutty recordings are magnificent, to name but one. I believe, however, that it came into 'Folk' music in the early days of the revival when people like Alf Edwards were regularly called upon to provide accompaniment on recordings of McColl, Lloyd et al. It was earthier than the inevitable guitar, which certainly had no traditional place for all its prevalence, and offerred the singer a full range of keys. This full range was never felt necessary by musicians who would play all night in the same key as many still do. (The fiddle has thousands of exponents in the tradition, but name me one who uses the full range of keys that are available!)
The conventional explanation for the separate CVs of the two most popular concertina systems is economic. At the time when Jeffries was selling Anglos for a few shillings the Wheatstone English was costing a Victorian arm and a leg. Not surprisingly therefore the English went into the Victorian parlours and drawing rooms and soon attracted its own designated repertoire while the Anglo went to the working class where the repertoire was traditional/popular. I think an additional factor was probably that the traditional musicians were non-readers and the Anglo is much more straightforward for the ear-player. The ease with which basic chords fall almost automatically under the left hand and the right hand finds the major scale easily on just a few buttons make it possible for a player aith a fair ear to be playing functional dance music in quite a short period of time. Remember that function is the real issue for the traditional musician, whether playing dance tunes or popular songs.
The discussion in the forum stems from a desire to get into more keys and therefore is another form of the belief that the Anglo is a 'restricted' instrument. I find this an odd concept: any instrument has restrictions. You can only get six notes at a time on a guitar, four on a fiddle, and so on. A lot of respectable orchestral and jazz instruments produce only one, but nobody suggests they are restricted!
It is the issue of musical key that brings the Anglo into the firing line. Yes, of course, the full sound with full chords, and the ease of playing which I mentioned above apply only to the two main keys, but with a bit of practice is is quite practical to go up one key and down one i.e. into D and F on a C/G. Of course, the 'feel' is different, twiddles and diddles come less easily, but the resulting smoothness that comes from the flat key is highly desirable on occasions.
If you are playing on a 39 key instrument then much greater possibilities are available and although I do not personally stray far outside my home keys I can get all the major chords (some a little thin perhaps) from 4 flats (A flat) through to 5 sharps (B) with relative minors and all the augmenteds and diminisheds. Of course this imposes limitations because as you get further away from the home keys the chords become available only in one direction, but this can be worked around.
I once saw a collection of diagrams for the button layouts of concertinas. If these were more easily available it would help potential anglo players to calculate the range and scope of the instrument that they were thinking of buying. Also I used to include a sheet of bass chords as part of the documentation of my Anglo workshops and I know that someone somewhere has transferred and extended these into a multi colour Excel Spreadsheet, though I can't now remember who, though I'll bet it was a Concertina.net contact who could well be reading this!
I have recently received review copies of two CDs (good ones in my view): The 'Bunch of Keys' from Jason O'Rourke and 'Tracin'' from Gearoid O hAllmurain, which both include in the tune notes the pitch of the instrument being played and this confirms the fact that the Anglo is usable to a very high standard outside the home keys, especially in the Irish styles where big left hand chords do not play a prominent part - and usually no part at all. This ties in with my personal memory of occasions when Tommy McCarthy would come to music sessions at my house in Islington. The sessions were invariably in G/D, but Tommy would always ask me for a C/G box to play in those keys.
Also relevant here is a hand-written booklet that came to me together with the 38 key F/C Jeffries (high pitch) for which it was written and which I have mentioned before when discussing even and uneven temperament elsewhere. In this booklet, Jeffries (for I am unshakable in my belief that it is his hand) gives the fingerings for playing in C, D, E, F, G, A, B, E flat, A flat, B flat, F sharp, C sharp, and then the full Chromatic Scale. Now much of this would sound out of tune on uneven tuning but the man who made the box intended it to be possible with even temperament.
So to someone who is able to buy a new concertina to help solve key-based problems my advice would be to stick with the Anglo because of all its strengths but buy one with 38 / 39 buttons.
One word of warning. Unless you are a real expert, DON'T try to solve small problems by moving reeds about. Reed shoes forced into different positions can be too tight or too loose and the tuning will invariably be out as the pocket of air in which the reed vibrates can change the pitch of the reed by up to 10 cents.