The caves booked for this North Pennines field meeting have a fixed number of cavers permitted each day. If you want to be sure of getting a place on your first choice cave - please get your booking in ASAP via the BCRA website. First come First served. The choices are all remarkable caves in their own right.
You do not have to be a BCRA member to attend this event. 
Perhaps the moderators will allow me a head start in "Caving Chat" before banishing this post to "BCRA"
cheers
Andrew