Hy Les indoor camping is when in the cold climate of Britain at Easter it is far too cold to take your tent to a venue
The indoor camping makes use of community halls, scout huts, church hall, youth centre venues and similar and permits singers and musicians to bting their matresses airbeds sleeping bags etc and sleep together communially (yep great fun) often singing cinbtinues well intop the night and breakfast may be late!!
Barnsley is just such an event using YMCA Community hall next to the town centre and all amenities including late night pubs/clubs and fast food outlets if you wish
A great experience on a smaller scale to the big outdoor festivals and adopted by many UKL festivals