Hi Trev, not based up in the NorthEast so can't grab you expertise for a day
The main thing is not the physical install, that should generally comply with BS7671, the tricky bit is in the design and getting that right - and that's where most of the poor/ bad installations come from - poorly / inadequately trained (if at all..) designers.
We have visited over 40 installs by others over the last 8 months or so, and so far only found 1 that was 100% compliant with the standards (I'm sure that someone could find fault with some of ours as well if they wanted too as we're not perfect).
Most were 'OK' we have found 2 that were dangerous and we immediately isolated shut down and locked off (much to the owners chargrin) and lots that if a little care had been taken over would have been a lot neater, - i.e they will work, they were safe, despite being 'scruffy'
Out of the 40, I'd say that we would be happy to put our name to 2 of them..
If you are with a switched on, well trained sparks, on a day you should learn the basics of the isolation requirements, cable routing, labelling & testing, and they may be able to give you a heads up on panel locations and shading, however this document will give you a lot more information:
http://www.microgenerationcertification.org/images/PV Book ELECTRONIC.pdf
