The fan is in and working, thanks to everyone for their help, especially Phillrulz who's wiring guidance was greatly appreciated.
I took Phil's advice and put in an additional relay, with a fuse, (convo happened on another thread), you can see below, top part is Phil's and bottom is wiring diagram from the Minispares Revotec kit.
I am a bit peeved their wiring instructions didn't explain it properly, I know they can't cater for all, but some clearer explanation would have helped. Especially as to why you should have a switched live, it would have saved a lot of head scratching, especially considering this is meant to be a ready made kit for a Mini. They didn't include the earth wire from the fan, talk about penny pinching.
I couldn't use their brackets to attach straight to the rad, as there wasn't enough room in the engine bay, so my Dad kindly made some brackets to attached to the inner wing. They will be painted, shown unpainted in the test fit photos below. Similar to Azbornmini's brackets, some steel and some 3/4" tap washers from Screwfix, which are 25mm wide and drilled out to fit the M8 bolts, which I had to buy.
I can confirm it works fine in the wing and disperses heat very well.
Edited by beardylondon, 07 June 2019 - 07:36 PM.