So does this mean that technically you can take your skills test at any time after all exams are completed, solos etc, make up the hours to 45 then apply for the liscense?
Actually, I'm not even aware of a regulation that specifies that you can only do your skills test after having done all the theory exams.
The only regulation I know of, and as others have pointed out, is that you have to have done everything (45 hours total, 25 hours dual, 10 hours solo, simulated instrument time, theory exams, skills test) before you send the paperwork off to the CAA.
If you've met the prerequisites, ie. 25hrs dual, 10hrs solo (which can include your QXC), you can do what you like with the last 10 hours. Knock out a night rating (sorry, qualification) if you like, although I believe that even that could technically form part of the aforementioned 35hrs.
True. The five hours for the NQ rating can be part of the 25 hours dual and 10 hours solo. Important is that of the three hours dual some need to be a cross-country, not just circuit bashing. I don't remember a specific distance like the QXC but it has to be to another field. There is no minimum number of solo night hours required, just five solo circuits (with stop-and-goes - touch-and-goes are not allowed).