There is no restriction on conducting the IMC Rating / IR(R) flight test; as others have said, FCL.1005 does not apply.
If the UK is successful in its call for the re-introduction of JAR-FCL 1.175(b) as FCL.600(b), then some amendment to current practices will also be recommended. For example, 'advisory' minima should become obligatory - and testing in accordance with FCL.1005 will also be recommended. However, there will also be a need to define requirements for IR(R) instructors and examiners - AOPA has already suggested this to the CAA, but they weren't prepared to include it in their conversion report at this stage....in case EASA made them cry