The 70 hour figure refers to the conversion of an old-style pre-JAA UK PPL into an EASA part-FCL PPL.
You need to have 70 hours or more on aeroplanes and to 'demonstrate the use of radio navigation' in order to convert an old-style pre-JAR PPL(A) into an EASA part-FCL PPL - as has always been the case for converting to a JAR-FCL PPL(A).
There are no changes to UK-issued JAR-FCL PPLs; these will automatically be considered EASA part-FCL PPLs and will only need to be physically exchanged when the 5-year re-issue date is due, whereupon it will become a lifetime licence.
It would seem that with an EASA part-FCL PPL, you will be able to exercise the full range of Rule 28 VFR privileges - rather than being restricted as is the current situation unless you hold an IMCR.