Thanks guys.
It took two days to refurb the fronts, you could do it much faster with two hands and painting at the end, though it would be much more sensible to buy new ones. But I have time on my hands (hand, lol) and need something to occupy myself, so I was willing to put in the effort.
I started with a wire brush on the drill, that got all the really manky stuff off.
Then I spent ages chipping the corrosion off with a screwdriver. AGES.
Wire brush on the dremel for all the nooks and crannies.
Made sure all holes were sealed and gave them a really good wash.
Cleaned up the bleed nipples and banjo bolts with the dremel wire brush.
Coat of hammerite.
Removed the pistons with compressed air, be careful they come out with surprising force! Norv suggested using a grease gun, sounds like a great idea.
Endless hours of dentist pick and handheld wire brush to clean up the seal points. Worth taking the time over to get a good seal.
Really, really good clean. Air dried over radiator to prevent contamination.
New seals and piston covered in lube supplied with kit.
Piston seal situated in caliper.
Weather seal put over bottom of piston, with the caliper end hanging off the bottom of the piston.
Piston and seal pushed into caliper, slowly push piston in and try to situate seal in caliper.
Once the piston is 3/4 in, situate the seal on the piston.
Coat of hammerite.