Suspected blown fuse

Hi Dan, Unfortunately if you have already changed the 5A fuse, and I am assuming that you mean the rewireable fuse carriers, then you have already done all that can be done by a non-qualified person. If the fuse had blown you would have noted the fuse wire was in two pieces, if it was not then it is not the fuse. I am confused by your term "main 45 watt fuse" there is no main fuse, apart from the main cut-out at the service position and you definitely do not want to touch this under any circumstances. Please just use this site to get an electrician in to help you.

Fuses are rated in Amps and not Watts, so the question is a bit confusing. However if fuses shave been replaced and were checked as OK before fitting and the lights are still not working then it very much sounds like a loose or burn connection problem somewhere on the circuit? Only thing to do really is to check for voltage at some of the light fittings and also carry out a continuity test with a test instrument. If you don't have one to hand or are not familiar with how to test the circuit, then best your bet is to post a fault finding job on this website and get some quotes. Most likely fixable in a few hours once the type of fault is identified.