As has already been said, it depends what flying you have been doing.
If it is just AEF flying in the Tutor then generally you can't count it.
According to the CAA you can count 10% of time as captain in the Vigilant towards an SEP ("light aircraft") PPL, up to a maximum of 10 hours. Unfortunately, unless you are an instructor on the Vig this (or going down the motor glider PPL route) probably won't be much use to you.
You won't be able to count any Viking time towards a powered PPL.
As A819 says, it's all in LASORS:
LASORS: LASORS 2010 | Publications | CAA
Have you been on the Air Cadet Pilot Scheme? If not, apply as soon as you can. If you get on the light aircraft course, you will get 12 hours at a civilian flying school, all of which counts towards your PPL training!
Hope that helps
p.s. A819...where are you from then? I don't have a copy of the old callsign allocations to look you up!