Hi, I had the same problem last year and this is what we did!!! We used Delta Force in Thornbury, and it was younguns package - so under 16s. This avoided the stag groups and 'professionals'. They had 6 games throughout the day and safety was a huge factor, they did not accept any excuse for rule breaking and took people out who did - such as removing helmets etc. All equipment was provided as well as a pizza for lunch! However, it wasn't cheap. We went for the £20 package which included 300 balls, I then rationed them to 50 per game, but still ended up buying more, they get very trigger happy! The boys had a great day and the dads even better, all wanted to do it!
I couldn't fault the organisation or day, but if you do it with another family it does keep the cost down. I hope this is of use!!!