Will the IFR/4 = IF be used to convert post PART-FCL implementation
No it won't, see
AIC W13/2012
The CAA introduced the 1:4 rule because they employed pilots who understood that 200 hours of flight in accordance with IFR was both unverifiable and irrelevant. Looking at Para 3.2 it is apparent that the author of the AIC has little understanding of IFR anyway
3.2 Applications from 1 July 2012 for privileges granted under Part-FCL requiring the individual to have completed a minimum number
of flying hours in an aircraft in accordance with IFR will only be accepted where the required experience has been gained in flight in
circumstances requiring compliance with IFR.
There is no JAA or EASA requirement for the IFR experience to be gained under the quoted circumstances.
Once upon a time AICs were checked for inaccuracies before they were released, now it seems they are either not checked, or they no longer employ staff with sufficient knowledge to spot the mistakes.