I agree, AIRPROX them and let the CAA decide on whether an arse kicking is needed.
As for everyone else, isn't there something more important to glean from this thread....?
The importance of checking above and behind prior to departure (10/10 vfrpilot - there are loads of pilots out there who wouldn't have been so diligent)
And keeping a sharp lookout and careful planning prior to and during low level flight.
We have all seen GA traffic blundering about oblivious to what is going on outside, SEE AND AVOID.
Personally I see the Lake District and avoid it - Too much of a fast jet play ground!