Thanks Nessie. I had same response ref 2nd opinion. Haven't had the 50% offer yet though. Visiting and threatening suppling dealer with Small Claims action tomorrow so may try SMMT if no response. 50% of £1100 is more than doing the job myself.
I got good response from registering with www.partsgateway.co.uk
when pricing 2nd hand seat so that I could minimise replacement cost in order to proceed thru Small claims where you can only reclaim money owed and not enforce dealer to take corrective action. Does anyone from Renault read these comments?