instructions for replacing brake light in rover 25?

Answer 1

Not the easiest - you have to pull the carpet-like boot trim away from behind the lamp.
From there the bulb holder comes out of the lamp cluster by twisting slightly and removing.
Twist the bulb to remove, fit new bulb in bulb holder, refit bulbholder to lamp cluster.

Now comes the really hard bit - trying to fit the boot trim back into place beneath the tailgate rubber and the plastic trim beneath the tailgate opening. I don't think mine ever went back properly.