Thank you one and all, some useful info there. I especially like the Farnborough LARS leaflet, I shall re-read that more than once to ensure all is fully understood. And I think I'll have a good chat through with an experienced chum before I start to think too seriously about it. I may even pop back into the flying school and ask them to cast an eye over the scribbles I've drawn on my chart to double check I've not missed the obvious anywhere.
Airpolice - I'd dearly love to go through the TMA with a choice of altitudes available to me, but on my chart it's shown as Class A airspace, and as I hold only a PPL and no IR, I'm not allowed to - for jolly good reasons which I fully understand. A 'spam can' isn't of nearly the same performance as an airliner, so would get in the way quite a bit. And it would probably be swallowed up whole by the big sucky, spinny, noisy things hanging under the wings of (say) an A380 if I did get in the way. Add that to my list of things I'm allergic to.