So, pretty much on track with the build, but the only other sticking point was the audio installation guys: They turned up to do me a quote (considering that I have already bought all the hardware), and asked them if they would replace some bulbs in the dash with LEDs and tidy the wiring in the frunk....
The two guys could not have looked less interested or enthusiastic. I don't know if they were intimidated by the car, but they made no suggestions at all, and every time I asked 'could you do this?', they just shrugged and said 'guess so'.... They then sent me a quote for £989.000 to install my head unit, amp, speakers and subwoofer....
I guess I am looking for another audio installer.....