One of the blocks of flats around here is undergoing extensive renovation and is currently empty, but I'm not sure if it is one that is already mapped.

amenity=swimming_pool is deprecated and doesn't render well. Please verify that this is a swimming pool and also confirm whether or not it is open to the public.

Assuming it is not open to the public, please replace the above tag with both:

leisure=swimming_pool
and
access=private

The nearby sports pitch should also have access=private, if not open to the general public.

Is there really an impassible ditch ringing and isolating this part of the park, or is it really just a topographical depression as part of the landscaping. Also, it looks like the land cover is different from the grass of the main part of the park.

Note ditches can only be used as linear features.

With the exception of one, unsigned, overgrown footpath, this area of grass seems only to be accessed via private alleys. That's a strong indication that access=private, but it requires a user of the ground or someone with very local knowledge to say that for certain.

There is housing on the East side of home zone part of Waterside Close, which should probably be mapped as the other housing in the area has been mapped.

The exact routing here and the alilgnment of the bridge and stream are uncertain because the tree cover was both hiding them from Bing and disrupting the GPS solution. It may need more GPS traces or some dead reckoning on the ground.

The stream direction is arbitrary, as I forgot to note it.