We've just been through the same here...
Problem 1 was poor running - turned out to be a split in one of the HT leads inside the head.
Problem 2 (just after problem 1) sounds the same as you - sometimes start, sometimes not, often starts then dies out...
The AA said it was the catalytic converter...
Nationwide said it wasn't the Cat, it was the
A Renault dealer said it was either loom or
- it turned out to be water damage in the
The rev limiting is not a fault, when there is an engine fault the
puts the car in limp home mode which limits the revs.
One of the main lessons is that all fault diagnosis equipment are NOT the same, worth getting it checked on proper Renault equipment.