When I took the calliper off and got an airline to force the piston out it wouldn't budge so I had to resort to vice grips with some padding so as not to damage the brake piston. Once they were out I used a Dremel with a brass brush to clean out the salty crud that was in behind the seals. A good clean with brake cleaner and a blow out with the airline cleaned them up nicely.
I have read loads of different opinions on forums about brake seals and red grease so decided to soak the new brake seals in fresh brake fluid and apply red grease to the outside of the pistons before re-fitting. No doubt someone will tell me I should have done it differently.
I also bought some new pads and braided hoses which help beef things up a bit. When I came to bleed the brakes I found that the reservoir screws were made of cheese.
The cross heads promptly dissolved at the slightest touch so I had to resort to putting a slot in the screw heads with a flat screwdriver and a hammer! They were so soft it was quite easy. I have replaced them with stainless screws.
I went to Newark auto-jumble today and bought some steel for making something for the back of the seat and a crusty looking item for the rear light.