'.I'm interested in playing English, Welsh & American folk and contemporary songs/tunes.'

The key issue here, Mack, is whether you like your music with or without chords. If you want to play some songs and/or morris dance tunes, the chances are you will want to add chords, in which case you'll need to find the melodies mostly on the right hand of the instrument, so that you can leave your left hand free to add the accompaniment. Chris Sherburn is a fine player, but chording is not really part of his style. The first anglo player I ever heard (the late Mel Dean) created a one-man-band sound, and that was immediately what I wanted to do.

The other thing to bear in mind is that, if your instrument is in C/G, its home key (i.e. C - the G row is quite high-pitched) is not that in which a lot of folk tunes and songs are usually played and notated. This sometimes confuses beginners, who read the sheet music, tie themselves in knots trying to play in D, and end up playing the melody across both hands (as Irish players generally do) so they can't then fit any chords in. I've had to take a couple of pupils right back to basics because of this very problem.

I think Steve's suggestion that you have a go at a few basic morris dance tunes by ear is a very good one. That's exactly what I did 40 years ago, once I'd graduated from playing nursery rhymes the Sankey & Moody hymn tunes that my grandmother used to sing. Although I can read music myself, the anglo concertina to my mind is very much a 'play by ear' instrument, and good old trial and error will get you a long way. Of course there are benefits to getting some teaching, particularly where chording is concerned, but if you've got a decent ear I bet you can work out a few tunes for yourself. Things like 'The Grand Old Duke of York' or 'Donkey Riding' are good starter tunes.

Look up some English-style anglo players on YouTube: John Kirkpatrick, Cohen Braithwaite-Kilcoyne, Keith Kendrick, and er.... me. But check out Chris Sherburn, Noel Hill, Mary MacNamara as well, in case you decide that you prefer Irish styles after all (Sandman will know other names). Jody Kruskal might be of interest if you want to hear American tunes played on Anglo (though he plays a lot on a G/D).

If you get stuck, I have been known to give lessons via Zoom.