Two cars in Gatso piccy?

[Marshy]

OK, so I'm cruising out of London last night along the Marylebone road, giving friends a life home. I am, as always, the slowest car on the road in London. I'll accelerate briskly up to speed, but I stick to the limits, while everyone else buggers off past me, clearly cognisent of where the Gatsos are, because they're local and I'm not. One of said locals, driving an Alfa GTV with the top down, and only on sidelights, overtakes me in a dual carriageway section, where there's a 30 limit. As he passes me (doing about 40-45 I estimate) we both pass a Gatso, which fires. Two flashes, which I guess means it has film. I look down at my speedo, reflexively, and realise the needle's on 35. Now, the trip computer in the car, which seems pretty accurate, reckons that in indicated 35 is actually about 32. Still, technically, speeding. Question is this. The person who looks at the Gatso photo to decide what to do is clearly going to nab the Alfa for doing 40-something. Are they going to work my speed out from the lines on the road? And do they employ the same tolerance levels that a Gatso does? i.e. only book me if I'm going over 30-something, rather than over 30-dead. I'd be so hacked off to be nicked by a Gatso in this situation: I was genuinely just about the slowest thing on the road... Edited by Marshy on Wednesday 13th June 12:09

[Marshy]

Thanks chaps.