Here's an update for you Nev.
Upgraded the lower bracket to 8mm, pad welded. Moves the mudguard over about 6mm, I think this will still look alright. As suggested, made a simple brace goes between bracket and axle. Chased out all the cracks, splits etc with a flap disk. Fibreglass repair and putty done, sanded back, ready for priming.
It's a bit humid here for painting. I am still a bit confused about paint, haven't done any automotive spraying before, but want to learn.
Reading the forum, I decided on 2K. The paint shop had no problems selling me 2K primer, but all the autoshops tell me I shouldn't be using it, illegal for private use at home apparently. I have read all the data sheets and have the respirator etc, so I am well prepared for 2K. I'm thinking I should return it and buy acrylic or enamel, but not sure what sticks to what, and will be best for the job.