Day trip from London with teenagers

[lemontop]

Hi

Have been asked to suggest somewhere to take a group of teenagers on a day trip travelling from London by public transport to somewhere outside London that isn't Brighton. Somewhere with cheap things to entertain teenagers would be ideal if such a place exists. I thought about maybe Oxford or Cambridge but not sure that'd be exciting enough or maybe Thorpe Park but that might be a bit too expensive.

Any suggestions would be gratefully received!

Shame no Brighton, I'm sure they'd love that, especially as its beach weather :)

How about Chessington ??

They have already been to Brighton so wanted to try somewhere else. Another seaside resort would be ok if there's anywhere as easy to get to?

Windsor, Castle and Legoland?

What about Hastings then ??