Bookworm
As those regulations stand it would be illegal to depart France in CAVOK use the EIR to a destination in the UK where it was IMC with an IFR approach required even if you have an IMCR
There is no accommodation in the regulations for the IMCR and UK airspace
That accommodation needs to be made
Will the CAA want that ?
Effectively such an accommodation would in UK airspace give the holder of an IMCR and EIR IR privalages
Ie IMCR for IFR departure arrivals and EIR for enroute airways!
A UK airspace only pilot would not need to get an IR as in reality he would have one!
My guess the CAA will say one or the other
Use the EIR as per regulations or the IMCR as per regulations but not BOTH
Pace