I may have read this wrong but the implication seems to be that if you have an imc rating you will have an ir(r) which gives you the same privileges as current imc rating. But for no more training you will also be able to get an enroute ir which will allow you to fly in airways across Europe including in the uk.
No, you
have read that wrong. There are no credits towards the EIR for the IMC rating -- you have to do the full 15 hours. There
are credits towards the CBM route to the IR, to the extent that an IMC-rated pilot may require as little as 10 hours.
I've seen this complicated EIR+IMC thing mentioned a lot in the discussions on FCL.008 over the years. Keep it simple: if you want to fly approaches and the IMC rating alone doesn't give you what you need, do the IR.