GJ,
I think you may have mixed up two seperate things here.
I haven't got lasors in front of me for the exact wording, but here goes.
The JAR PPL and CPL are both valid for 5 years, but obviously to use the priviledges you must hold a valid appropriate class of medical and a valid type or class rating for the aircraft to be flown. The licences do not have currency or revalidation criteria that I am aware of.
There are also seperate criteria for currency for carriage of passengers etc.
The 12 hours 2 years bit is the currency requirements for the SEP(land) rating. It is valid for 2 years and can be revalidated by experience, namely with 12 hours PIC experience in the second year and 1 hour flown with an instructor. Alternatively if not meeting the 12 hours of experience, through a single proficiency flight test with an instructor. In the event of the rating lapsing then I believe it's a flight test with an examiner for renewal.
In theory I believe you could sit on your PPL or CPL for 4+ years with no flying and your licence is still valid. What wouldn't be valid would be the class rating which would obviously require training and test to be renewed.
Hope this helps and Lasors is your friend for this,
Obs