These are the sort of landscaped spaces that I do think should be considered. They have been left as open space so that people can use it for social and exercise activity. It is often laid to grass simply because that is cheap. But it is totally accessible.
I would start to look at council websites as they will typically be responsible for the upkeep. Find out how these are described. Finding the planning consent online will often yield that these are meant to be considered recreational space. Finding an anchor point might be tricky.
Try to ensure the google maps has an appropriate label that matches what you find in the research. A supplementary picture on a nice day with people playing or sitting around will also help.
Overall it wont be easy but this is what people are likely to gravitate towards and not the estate sign. And I can see people spending time there.