I think the Crabshell is only on the first Thursday, so it wouldn't be on that week. In fact it's a difficult time of year, because some sessions and clubs shut down anyway because of clashes with festivals etc.

Check out the South Devon possibilities on www.harbertonfolk.co.uk. This is kept pretty well up-to-date so it's worth looking up at the last minute.

Cheers,
Marje