Have been doing these for a while now and they seem really popular. They bolt to the standard fixings on the front of the crossmember and have extra fixing points at the rear for added security. These can be rivetted, screwed or use rivnuts to fix in place. They then allow you to move the seat further back, ideal for those with longer legs or if you just enjoy a more comfortable driving position. £27.50 per pair (enough for one seat) and will do free postage to forum members.