you will probably be told to fudge off tbh. Its a reasonable request to cover lost time and any damages to the property but most manufacturer's couldnt give a monkeys and as for plumbs........... well.
If you speak to Ray Stafford he will tell you where you stand from a legal point of view and what would be the likely result of you asking the question.
In legal terms, you almost certainly don't have a leg to stand on. All merchants (including us) have terms and conditions of sale which include a "no consequential loss" clause. I can't imagine that Plumbs terms and conditions are less tight than ours!
However, in RM you are dealing with one of the best and most helpful manufacturers in the country - so long as they are asked nicely. RM is a privately owned firm, and do their manufacturing in the UK, so you are not dealing with a faceless corporation or an importer who has no interest in quality control.
In our experience, if the fault is genuine, and the labour claim is reasonable, they will look after you. We sell thousands of RM units every year, and have perhaps one problem every couple of months. However, if you scream and shout and stamp your feet, as like as not, the shutters will come down, and they will tell you where to get off. LIkewise if the cylinder shows signs that the fitting has been over-tightened with 36" stillies, then they won't be afraid to say so.
A lot depends on how the Plumb Centre manager handles it on your behalf. As I say, you are dependent on the goodwill of both PC and RM here.
Best of luck.