meabh - I think it may depend on the age of the car.
I bought my 2009 Roadster in UK, got a COC from Morgan and registered in France without an issue given it was more than 6 months old and had done more than 6000km.
I bought my M3W (LHD) in the UK, VAT Free, with a Morgan COC, paid the VAT here and again didn't have an issue.
