Just done this very job for my mot, courtesy of Steve, and it's a simple bolt on repair.
Two things, mark position of old one and fit new in same position, having checked that length of new = length of old, if not, adjust accordingly, this will hopefully keep the correct adjustment for the headlights.
Secondly, I found it easier to carefully cut the old one off, using an angle grinder, as my fittings were rusted on solid, and the rest of the assembly is a bit lightweight to be riving away at rusty nuts and bolts.