Does the radiator need to come off to do this or can it be done just by moving it forwards a bit?

Mine doesn't want to move very far forwards, it just about clears it's mount brackets before the hoses feel over stretched.
TBH I might just remove it anyway as I'm gonna need to drain it down anyway but it'd be nice to know if it's possible to at least do the check without removing the rad.

It can be done without removing it, just move it out of the way as far as the hoses let you.
Never had to adjust the clearances with it still mounted, so don't know about that.
Checking the clearances with the rad removed is a lot easier though!

Thanks nampus.

Seeing as I do now need the drain the system anyway and remove the radiator I'll just do that first and make this job a bit easier.