I'll start soaking them with Inox.
Don't seem to have much success with any penetrating oil - stuck seems to stays stuck - even with days of soaking.

I got the impression the bolts mentioned were something other than for the caliper guides.
Will have to look at the mechanics on the car, as the description in the manual is just awfull.

Yes, no doubt it will have dirty brake fluid.
Going to bleed the whole system to flush it all out, as part of the job (been in too long already!).