While we’re on the topic of the Thames, just checking in as to whether anyone is able to shed any further light on the helicopter routes - they show as a warning in most of the apps showing NATS data etc, rather than a restriction, and I have not been able to find any legal basis on which they would be restricted (which makes a lot of sense given presumably helicopters would fly at above the permitted drone altitude anyway).
@nathankw I saw your post over at this thread where you discuss the area to the east of Tower Bridge and you seem sceptical but I would have thought this is actually pretty clear cut - as long as you’re east of the bridge, which is essentially exactly the border for R158 so a nice clear visual barrier, the next Eastward restriction is actually R159 which comes before the City Airport FRZ, so there’s a good 2.75km / 1.7 miles between them horizontally. Within that window, there don’t appear to be any other restrictions over the Thames (we know R160 does not restrict us, and on the assumption that I’m not wrong about heli-route H4).
This is all assuming a sub-250g flight with all the other standard drone code provisos re altitude, LOS, only when wind is safe etc.