Geehova: But not impossible, not even unheard of in that part of the world.
As it only lasted 15 minutes it's not the whole sortie, and possibly just a chance encounter by a three ship bouncing a pair.
This is back in the days when there were enough people flying around in the UK to meet up with some passing trade.
F3s might be more likely to do this stuff 80 miles east of there, in their traditional play area.
I know I couldn't tell the difference between a GR4 & an F3 at over a mile while it was manoeuvring, even with binos. Could you?