Okay, starter for ten.
What, exactly, are you asking for?
Is it:
A)
Wichety Grub 
A) Retention of the UK-valid IMC rating (as now) as a "national rating"?
B) Creation of a new EASA-wide IMC rating?
If the intention is to petition to retain a national rating after EASA take over all FCL then IMHO you're on a hiding to nothing as one of the "benefits" of EASA is standardisation across FCL.
If the intention is to create a new EASA-wide IMC rating then the next (first of many) question will be how you might handle the French (to name one) lower airway structure which, unlike the UK, isn't predominantly > class D?
Is the expectation that France will suddenly accept 15-hour IF pilots into their airways systems?
Is the expectation that they would "uprate" their airways to C or higher?
Or is the expectation that the EASA-IMC rating would not allow IF in CAS at all (unlike our current which allows IF upto D)?
Fairly basic stuff which needs to be discussed if this is to be a meaningful discussion, yes?