Thank you for your responses.
Arm ... : Some things I hadn't thought of. Thanks.
Vigilant Pilot : What does A-Level mean in this context? (They didn't do formation flying in my sixth-form!)
Nigel On Draft : I can see the sense in getting closer (within reason!), but is the exercise trickier with a prop, or not THAT close? - I'm thinking of momentum changes etc.
Edmund Spenser : Wow! I'm guessing the speed range of the Harrier makes it even more challenging, and thrust vectoring (air disturbance)/ back of drag curve?