If all you need is peer to peer, grab a couple Lucent cards and go for it. You don't really need an AP ( base station) . For net access set up one box as a router - Win2K or *nix does well.
We are a wireless ISP, among other things. I really like the Lucent cards because they work with every OS we run across easily.
The teletronics 2MB cards are also nice, linksys is so so in my book.
Not sure if the UK has any laws regarding wireless, might want to check.
Good source for cheap ones is ebay if they'll ship overseas. 80-100 US or less.
Don't have any spares or I'd offer you some.