It all went ok so I thought I'd add a picture or 2 to help someone else save a few quid. If you don't have steering wheel controls you don't need the expensive adaptor and as a bonus the buster mod is already done on the cheap adaptor. The only mods I had to do were add the amp remote wire and I added a ground although I don't think I even needed to that but it was recommended here. I still don't seem to be able to arrange anything on this forum so excuse the block of text and random photos. You can see the black wire I added to the pink wire no.12 in the diagram, I just shaved it and wrapped it around, worked perfectly and very loud!
Connects2 CT20NS03 Nissan 350Z 05> Car Stereo Radio ISO Harness Adaptor Wiring total cost delivered and fitted £2.99