Reading this it would be illegal and against these rules using an EIR to take off in IMC in the UK using an IMCR. in no place does it add that UK IMCR pilots may exercise the privileges within UK airspace and hence make compliance with these regulations.
As this stands to take off in IMC would void the legality of the flight and not comply with the privileges of the EIR
For those of us who haven't been on the Perverse Interpretation of EASA Regulation course, you might need to unpack that a little, Pace.