If you are looking for a GREAT youth group activity then have a look at Gravity Force. Seriously cool warehouse of trampolines split into various sections AND lots of fun.
I took a bunch of 14 and 15 year olds to Camberley and they had a blast.
There’s others dotted around though and new ones opening soon so there may be one nearer you.
Current price is £10 for a one hour session BUT you need to also add in £1.50 for the grip socks for your first visit (after than you can keep and re-use them)
Parents need to fill in the Waiver online (I got the teens to bring the e-mail confirmation to show that it had been done)