it ended up being the zf6 fuse being cactus. something so simple.
Upon ignition, the car goes through prechecks (is abs reachable, tok -> moves onto next check, is zf6 there (fail) then spat codes out. Codes were similar to the start of this thread.
As I got no response for a while from my post and didn't get emails I.e. to pour water on my ecu lol😀 I hadn't logged in for a while.
U1900
P1000
U1055
U1066
Thank goodness transmission control module in gear box wasn't cactus as this would have meant a more costly exercise.