Water tower art
The murals photographed on this page, which follows Central in On the hill part 1: South and central, mainly decorate a cylindrical concrete water container with a domed top.
I happened on the artist painting this one. He said its green and purple theme represents heather, which covers much of the east slope of the hill.
An older rectangular water tower (not really a tower though) is immediately to the south of the circular one with a domed top.
Ramsdown Hill in On the hill part 2: North, east, and west for more wall art