You could try AVforums, but they have very stringent rules and make sure you read them to avoid falling foul of the zealous mods
Another option is trading your kit in with someone like Mifsuds,London Camera Exchange, Ffordes etc etc.
Buy a copy of Amateur Photographer, comes out weekly on a tuesday, loads of adverts at the back
Don't reckon the Camera will fetch much, but the lenses will fit modern Sony DSLR's and might get a fair price for them
Gumtree is another outlet that could be worth a shot or one of the numerous free ad papers.
Not sure if there is a Sony users forum, but got to be worth a google
Ebay is the obvious choice, but becoming very expensive and heavily geared towards buyers. Good in one way, but there seem to be a lot of people trying it on and has put me off a bit (lot)
Other than that I don't really know, but good luck and enjoy your new camera