To be honest, I didn't even think Pontins was still running! lol
As above, stay somewhere else. With regards to the Burnham suggestion above. Seriously? I couldn't think of anywhere more depressing.
If you're after something like what Pontins offer (entertainment, fun fairs etc) then I would go with the suggestion of Holiday Resort Unity.
http://www.hru.co.uk/home
As mentioned above, it's right next to the fun fair and close to the beach.
Or, why not travel 15 minutes down the road and stay just outside of Weston-super-Mare.
http://www.purnholidaypark.co.uk/ still has the entertainment and swimming pool (indoor only) but is a good base to spend the days in Weston... which is much better than Brean (in my opinion).
It's recently undergone a massive redevelopment, and The Pier is great fun for the kids
http://www.grandpier.co.uk/
Either way, I would stay clear of Pontins :-)