Well there's a fair bit. The supermarkets and various other shops are stocking quite a lot of Halloween costumes and decorations, although the quality has slipped over the past couple of years and the shops are definately stocking cheaper items.
There are a number of special events in my local area . I'm taking my sisters kids to this one:
http://www.painshill.co.uk/showEvents/W ... dness.aspx
but withn a few miles there are also:
http://www.chessington.com/
http://www.thorpepark.com/
http://www.hrp.org.uk/HamptonCourtPalac ... tours.aspx
and a whole bunch of other stuff.
For Halloween, my wife and I are looking after my sister's three kids. We'll take them to the event at Painshill Park, and then it's a haunted boardgame in the afternoon followed by our annual ghost hunt in the local forest, then a barbeque in the suitably decorated garden (Jack O'Lanters and a smoking cauldron), and finished off by either Ghostbusters or Sleep Hollow (depends which way the vote goes).
Pictures of some of the loot I've purchased this year I've added as file links (at least I think I have...

Hope that's of some interest
Regards
Boo