Thank you for the details, I know that the wheel offset on my new wheels compared to the ones they used to measure the fenders is not the same - like I said, I think I made an error in measuring when I ordered the wheels.
But back on track - I think I cracked it
This along with some other small adjustments including some alterations to the bumper has given me (I hope) the clearance I need
Will not know for sure until I get the suspension all sorted out and the car back on the ground, but it is a lot better...
I also noticed that the small support that runs from the fender (under the light) to the side of the car was going to be in the way, so I relocated it further forward and behind the radiator mount - as you can see in the picture.