The Trades Club in Hebden Bridge would be the first venue to spring to mind. They have an eclectic series of concerts which will include some trad. alongside singer/songwriter, blues, world, dance and just about anything else you can think of.
The Topic Folk Club in Bradford is the next to spring to mind, although it depends if you want to drive or not, but they have an excellent concert series which deserves support as well as regular singing sessions.
There are numerous sing a round type sessions in West Yorkshire and details can be found on Jim Lawton's Filofolk website (part of the Tykes empire) at http://www.jimlawton.info/filofolk.
Hope this helps.
Described by Ralph McTell as "a terrific guitar player who also writes great songs"