EASA changes
If and when the EASA changes take place it will not matter a jot whether you hold a UK National issued PPL or a JAR complient one. The advice has not, from the CAA anyway, been to change to a JAR licence prior to the proposed changes.
There are significant delays in the NPA process to new EASA licences. There remains doubt that all will be completed in time for the planned 2012 deadline to be possible, more likely 2015. But as the process is secret it is impossible to know or make an intelligent guess at a date for complience. We don't even know what if any changes there will be.