Success at last.
Managed to get the maps loaded into the car and they are working great. All the roads around my work are now there at least.
It was dodgy USB sticks, the car didn’t like. I’m not sure exactly what the problem was but they just didn't work in the car.
I ordered 3 Transend 8Gb sticks from Amazon only to find there wasn't enough room for the files on USB 3. The stick held 7.52Gb and the requirement was for 7.58Gb. So be careful what sticks you purchase.
I ended up having to nip down to Tesco and buy another stick to finish off the upload. Luckily the car waits patiently for the 3rd stick. I also found if you stop mid upload it doesn’t mess up system but re-starts asking for USB1 then USB2 in quick succession.
The money I've spent on USB sticks, FSC codes and all the messing about, it was probably cheaper to go to the dealers