Den building courses with kids in Surrey / SE

[WinkyFirecracker]

I am looking for a a den building course that my partner and son can go on, preferable in the SE / Surrey? Has anyone been on one or does anyone know of any sites I could go on which run these courses?

I think Wilderness Wood in Hadlow Down might do them.

I think Painshill Park do them or you could try Alive Holt? They might do it too.