Thanks Hyperspace, that is some brilliant info! I think I will fit 235/35/19 as this will keep the same load bearing and I just hope I can find a suspension set up that will keep them from rubbing.
There are just so many different opinions that I think this going to continue to be a grey area and only trial and error will give the answers. I'm gonna have a word with my local tyre shop to see if I can get them to try a couple of different tyre brands as I'm sure this will play a major part too. I might just wait to lower the car first and take it from there?