I used to use the Ministry of Transport depot, couldnt go wrong with them.
I know the whole rip off garages thing and never used them unless work took priority, even then it was a local trusted one man band who just wanted it in and out and paid as fast as possible.
My point being the interpretation of the rules, as with all things drafted by central and local gov, they are open to interpretation due to the inability of the makers to be able to clearly define the subject.