Yep, thanks, the 150m was copied from the blurb about the ...residential, commercial etc... bit and I neglected to change it to 50m as per A2 regs. Of course, separation from uninvolved people (ignoring where they are for a moment) is 50m whether you have the A2 CofC or not.Sorry that is not quite correct - I think you have confused the Article 16 wording. It is for recreational flights only and not in built-up areas. There is an exception for recreational areas within a built-up area eg a large enough park, with a risk assessment. That does not allow you to fly over a housing estate! As it happens I did discuss with the Chief Exec of FPV UK flying within the confines of a back garden staying more than 30m from the neighbouring houses (or 15m with a risk assessment).
I'm afraid you were also wrong about A2CofC. In A2 transitional under 2kg you can fly in built-up/residential areas with 50m separation from uninvolved people. This doesn't help the OP in this situation but is correct.
The information regarding flying in built-up areas, at least on the FPVUK poster, is quite misleading then. It doesn't truly emphasise the part that it's an area close to an area (i.e. a model flying park close to residential). I know there's only so much they can do with short bulletpoints but they're not helping themselves with the poster I've seen.
I'll edit my original post to get rid of the 150m aspect. First time I've been caught out on that since January 2021 so not bad.