just got a quick reply
with the caveat this is for the RAF only
all aircraft (f3, gr) were initially given the 4 ridge Tyre, however there were a series of blown tyres when the gr1's upgraded to gr4 (put down to extra weight) so at each service the remaining tornados were retyred to the 3 ridge which had an extra weave of steal in it
so..... depending on age f3's could be either
early gr1's would be 4 ridge, late gr1 and gr4 have 3 ridges
hope that helps