Welcome to UKBG. Fascinating website you have there!
Maybe someone with better info will be along to help you out, but I'm not sure if there are any regular jams up there round Lancaster. I know that there are regular jams going in Yorkshire at Hebden Bridge, Thornton and also Leeds, which would probably be about an hour and a quarter/hour and a half from your base in Lancaster.
See linky to thread below:
There's also the mini festival coming up near Runcorn, near the start of your visit (details on thread link below). That should take you maybe an hour and a half down the motorway. Saturday looks good. Tony Ellis is playing and there's lots more stuff going on. Not sure how much jamming will actually be happening there but a good opportunity to meet people and make contacts.