Thanks again, both.
Given that they are much cheaper than I expected, I'll definitely invest in an impact driver before starting the job. I might try to reuse the screws or even leave them off, given that with most cars the discs are held on by the wheels and brake assembly.
Note taken of the need for high temp grease on the sliders rather than Copaslip also, thank you.
Just waiting for the window of a whole day when I can start the job and finish it in time to do other stuff, and off I jolly well pop.