If you haven't yet revalidated onto the revised NPPL SSEA Class Rating system, you have only 5 days left to do so. After that you will require a renewal GST.
Under the former 'rolling validity' scheme, part of the requirement was to fly at least one training flight with an instructor of at least 1 hr duration in the previous 12 months prior to the date of flight.
Once you are on the new scheme, you may complete an accumulated 1 hour of training flying within the 24 months of the rating validity period. How and when is up to you.
I repeat, if you haven't already revalidated onto the revised scheme, the transition period in which you may do so expires at the end of 30 June 2009.