It been a while, but I think Esher college is just west of Thames Ditton Station, about 3/4 of a mile south of Hampton Court Station. As you head north up the A309 toward Hampton Court, Tiffin School's (I think) fileds are on the left, with Ditton Field up further on the right (Kingston Grammar). I suspect Tiffin might also be worth a go...
There is a pretty small park behind the station car park. I have no idea who owns it - but suspect it isn't council as it (used to be) gated off.