£450 is pretty good from a garage,
depending how close you are, (I traveled 2 hours)
Aaron's autos in Derby do them and just replace the joint for £175 inc vat, took them a moring to do it
It would be the same distance for me, but they clearly look like the guys to deal with this.
Do you know if it is a part they have commissioned / machined themselves or is it the genuine Renault joint that they have managed to source on its own away from the hub?
Glad to hear your getting it sorted! They did it no hassle on my 200, in under the time they said, couldn't recommend them more.
A Toyota main dealer had the car for 3 days when the other side was done under warranty