Silly question I know.......but why on Earth do you have both a valid JAA PPL and a valid NPPL? Surely holding a valid JAA PPL would remove any requirement to hold an NPPL.
However, are you referring to the Pre JAA UK PPL as an NPPL.....This is not the case and if you hold a Pre JAA UK PPL then this JAA PPL replaces this PPL and should include all the ratings that were included in the old PPL.
As to national ratings of a JAA PPL.....absolutely no problem.....you can now get a UK IMC rating on a JAA PPL issued by France. The IMC is still only valid in the UK though.
Renewal reqiorements remain the same - 5 Hours in the previous 13 months or a Flight Test with a Microlight Examminer.
Regards,
DFC