Hi all, just wondered if anyone knew of any venues that are reasonably...

Hi all, just wondered if anyone knew of any venues that are reasonably priced? We're in South Yorkshire but don't mind to travel a bit. We'd like something a bit different, like the treehouse at Alnwick gardens but have no idea of their prices, or something similar? We will be having less than 25 guests that's including us and our two children. Any help is greatly appreciated, thanks you in advance x