It was faulty glow plugs causing the starting problem, despite no fault codes coming up!
Car starting fine now.
Now, to get that annoying squeaking from rear end sorted!
Emptied God knows how many tins of lubricant on all visible bolts, bushes, etc, on rear control arms and suspension, but to no avail! MoT tester wasn't concerned with squeaking in March. Been like this since getting caught out on flooded road at end of December.
Any ideas?