They're fairly easy to change from what I've seen. Unplug electrics, undo two retaining nuts and pull out. Not sure if any aux's need to be removed for access but looks fairly easy from what I remember.
Getting hold if some replacment ones might proove interesting though!
Its stripped down to the last nut and bolt so getting to them in not a problem, one has been cracked for years, held on with a tie-wrap. Thought it would be a main dealer thing, just looking for other ideas.