Thanks Zippi, I'm beginning to suspect its the EI unit. Checked the carb like you suggested and the mesh looks clear.

Also tried your starting sequence. Sadly, its the same result - pop with choke closed, no firing even when using a electric starter.

Will be travelling in a couple of days and really would like to get the plane up before then. Otherwise, it'll be at least a week before I get to try again.

Think I have a spare carb around somewhere. Will try putting that on to see if it makes a difference.