I played crumhorns, shawms, racket and recorders in early music groups for years in the '70's and '80'S. I was also playing in a folk group (The Wakes) during the '70's which used all sorts of instruments, and we naturally explored the possibilities of using crumhorn. It worked well with concertina or Indian harmonium. It's an instrument that works best with other crumhorns, or racket, or regal (an early reed organ), but can work with mixed groups, and does seem to work well with free reeds.
Interesting to see Mike from Rebec is still around. Rebec were doing the rounds at the same time as The Wakes, and we used to see Rebec's name on club guest lists - usually the month before or the month after us, but we never met up. I did see the group finally, at an early music day in Chester, in abot 1981, I think. The other Rebecs, Bob and Anne, later played with The Chester Waytes, of which I was a member. We had a full 'loud band' - shawms/sackbut, as well as recorder and crumhorn consorts. Aye - them were t'days. J.K.