Started the car this morning no problem. looked under the bonnet to try and see if anything was loose etc but saw that the cooling fan was running with a stone cold engine. Drove the car about 20 miles with no problems and checked under bonnet again and fan was not running. Does this indicate anything.
Sounds like you have an electrical fault, but I agree with Dave get to your VX dealer to stick their diagnosis computer in, otherwise you might do more damage to 'whatever' is playing up!
I also have a Laguna2 and I had the same sort of problem that you're describing, I had to have the coils changed, however they remapped (updated my ECU with new codes) it ran lumpy to start with and it would hit the limiter at 3000rpm!! Anyway 5000kms later it eventually cleared..
Does it sound tappety?
Did you pressure wash under the bonnet at all because you may have still water somewhere causing the problem?
Anyway I hope you sort it out soon!! =)