No, it won't. Competence for sub-ICAO matters would be devolved to national authorities under the principle of subsidiarity. The Basic Regulation might need to be amended to support this, however.
There is an alternative strategy should the EASA €urocrats fail to accept the UK IMCR as it currently stands.
The pain problem is that the bumblers at EASA cannot understand that you don't need the same levels of training to operate to IMCR minima as you do to IR minima - and that such IMCR minima are entirely adequate for the vast majority of private pilots.