These might be helpful, if you've not already tried them:

http://www.yorkshire-folk-arts.com/    Select "YFA Directory" on the left, then about half way down click on "Sessions, West Yorkshire"


http://thesession.org/sessions/search?day=&q=lancashire

http://thesession.org/sessions/search?day=&q=yorkshire

The session at the Slubbers Arms in Huddersfield is still going strong, apparently, next one March 7th..

You've probably already thought of this, but your local morris side musicians might know of sessions.

Good luck,

Joy