Ok the last problem was my fault.
When I took the throttle apart the other day, I didnt put the little sensor back where it is supposed to be.
On the end of the three wires there is a small sensor which fits in a small space in the plastic, I left it hanging loose so the controller thought the throttle was slightly on.
Put it back where it is meant to be, I'll use a little bluetack to keep it there as it did have some kind of white chewing gum type stuff on it which I wiped off.
Working fine now i've put it back.
Just to confirm I did rule out the throttle to be the culprit at the start by disconnecting and reconnecting it multiple times which made no difference, so the parts sent were not a waste of time, just an error on my part putting it back together properly. I can conclude that the controller appears to be at fault, i'll update in a few days to check it all over.
By the way a factory reset on the LCD doesn't delete trip or odometer miles thankfully.
Inside the throttle: