I had a check here earlier but it's generally a waste of time checking the former sludge beds as it's so overgrown and impossible to view through the trees. There is a small area of phragmites and scrub areas as well as wet bog. Only chance of getting anything here is in Spring listening for warblers including still the possibility of Reed W, Sedge W etc. it's probably also ok for Water Rail.
The filter beds were just about viewable with c40 Pied Wagtails and at least 6 Grey Wagtails and 2 Moorhen with 2 Grey Heron flyovers.
Nuthatch and Gt Spotted Woodpecker in the nearby woodland along with c 15 L T Tits.