I've got 256mm rear brakes on my Fabia, but I've noticed one of them is occaiosnaly sticking..................I know with the 239mm solid setup, helper springs can be fitted to assist moving the handbrake caliper back to its "off" possition. Would it be possible to fit said springs onto our brakes?

If caliper piston/s sticking, then a fitment of a spring isn't gonna help things out.

Caliper piston itself needs to be cleaned at the very minimum, or replaced which might be a better idea.

If you had gone on the Fabia forum you would have seen this http://briskoda.net/forums/topic/137832-handbrake-cable-issue-on-my-vrs/

I might add that the pistons and rear handbrake operating lever may be sticking as well, lots of easing oil will help

If caliper piston/s sticking, then a fitment of a spring isn't gonna help things out.

Caliper piston itself needs to be cleaned at the very minimum, or replaced which might be a better idea.

Sorry, the arm itself doesn't spring back, I beleive the piston's fine.

It does spring back, when I pop a socket on the arm and tweak it, but there is no tension in the arm to return arm to normal place, while on the other side, the arm has tension and does return to normal place.