Currys digital in Southend (maybe also even nationwide?) have a good selection of PS2 games at only 9.99 and less (in the basket as you come in, next to the Xbox under £15 basket),
including Pro Evolution 6 * FIFA 07 * Tiger Woods PGA 2007 * Kingdom Hearts 2 and stuff like Singstar legends for £4.99
Lots of copies of everything except Kingdom Hearts, only a few. I know this is a local thing for me but most Currys tend to do this type of stuff.