One question will be what the privileges of a pan European PPL will be. Will they be an improvement on what is permitted in the UK, i.e. perhaps the ICAO minima? Then perhaps you will be able to get differences training to allow the PPL holder to fly an ILS
What you mean some sort of sub ICAO national instrument rating?
We could call it something like the Instrument Meteorological Rating in order to differentiate it from a proper instrument rating?