www.biggred.co.uk
sells the seals, but tbh I would forget the seals just try with an assistant pumping the pedal, take the pad out on the piston side and pump the piston out a bit and spray WD40 around it, then lever back in, do this a few times if there is no improvement might as well just get a pair of recon calipers, saves any hassle, and cheap enough on your car, I would guess around £35 each.
The caliper is a single piston sliding caliper, the sliders are not the best things ever, and don't slide as well as they should, due to the design the force exerted on the brakes when the pedal is pushed cause them to try and twist, this causes the sliders to bind to a certain degree, the pad wear you describe is TOTALLY NORMAL, piston side will always wear more.
tabetha