In simple terms, the old NPPL with a rolling validation of 13 months will expire on 29th JUNE.....NOT LONG TO GO !!! BEFORE THIS DATE :
You need to fly with an instructor/ CFI(PPL or Microlight) ,LAA Coach, CRI/CRE and do a 1 hour flight check and get them to sign your log book and licence to the new 24 month 12hr period( make sure that the are allowed to sign your licence, i.e an examiner.)
Failing to do this will require you to do a licence revalidation test.
Will.