I had a very bad experience with this company today (also trading under the name Crown Locks). I explained in great detail the problem with my broken lock, and asked for a maximum price I would expect to pay for parts. I was told 'between £25 and £48 for the part', however when the engineer himself came (very nice man, subcontractor), he fitted the part and then said it was £85! I explained what I'd been told on the phone, and he called them whereupon I found myself having to quote Trading Standards and asking for a copy of the recording of our phone call. In my opinion they deliberately quote a lower price by phone and then try to intimidate you into paying up if the part costs more.
I insisted on hearing the recording of the phone call, and all of a sudden they backed down, saying they did not know how to make this available to me.
Beware when calling around for quotes, as many of the numbers are the same company.