The thread on Renaultsport had an impact. Found out there is a solution on ACTIS which is apparently a fault finding database of somekind the RTE's use. If its a known fault its on there.
So I called RUK and asked about this and the woman said that this was the case although they at Customer Service dont have access to it. Therefore when I called and asked if the fault was a known fault and asked why the dealer wanted my car a FULL DAY, the telephonist checked on the top of her head to see if it was. Having never heard of the problem (which had been logged as ECU overheating lol!!!!!) she sent me on my way to my knowlegable Renault dealer.
So I called the dealer and mentioned the magic word ACTIS. They said call back in a couple of hours and I will have checked for you. I called back and they had actually CHECKED!!! Yes they said, that job will take 1.5 hours to complete, and we can do it whilst you wait, and we've ordered the parts already!!!!
SO, by virtue of me doing the groundwork, Renault have my car for 1.5hrs, not a full day. They will also definitely have the parts required to do the job.
Imagine how efficent they COULD be if they just did this in the first place?