A quick update, the coolant temperature sensor seems to have fixed the worst of the non-starting issues. The cars been mostly fine for the last month and started ran fine in the damp weather we've been having the last week.
The car still struggling to start occasionally with an uneven idle. I think Laird was right when he suggested this is a multi-faceted problem.
I pulled fuse 1 for the ECU and the lambda sensor trouble code hasn't been coming back. Will post a Youtube video next time the car struggles to start (will look a right berk videoing every start in the meantime!
