I can't speak for that specific roundabout, but in my experience if various approach roads have different limits then they'll typically have signs changing them to match shortly before entering the roundabout.
So the speed limit on the roundabout is the limit on the road by which you entered, but note that it may have changed immediately before entering.
In this particular case, I'd assume the limit is 30 mph: it's in a built-up area with street lighting, and a quick look on StreetView doesn't seem to show any signage indicating otherwise.
(Pretty sure that on some larger roundabouts, e.g. on a 40 mph road, I've occasionally seen the small speed-limit reminder signs, but I don't recall ever seeing an actual change within a roundabout.)
Source: UK driver, much prefer roundabouts to most alternatives. :)
So the speed limit on the roundabout is the limit on the road by which you entered, but note that it may have changed immediately before entering.
In this particular case, I'd assume the limit is 30 mph: it's in a built-up area with street lighting, and a quick look on StreetView doesn't seem to show any signage indicating otherwise.
(Pretty sure that on some larger roundabouts, e.g. on a 40 mph road, I've occasionally seen the small speed-limit reminder signs, but I don't recall ever seeing an actual change within a roundabout.)
Source: UK driver, much prefer roundabouts to most alternatives. :)