Thanks for all the input above.

I haven't tried the fluid soundfont yet.

I started with 32MbGMStereo, which was quite limited, and then moved on to Arachno, which has a good selection of instruments.

However, the best so far is the "Concertina" that Jim sent me: two beautiful concertinas together with the warmest accordion sample I've come across.

This should meet my needs.

I know that practicing along to MIDI files does bugger-all for learning the "groove" of a tune but I'm finding that it really helps with intonation.

Once again, many thanks for your help.

Harry