The final cache can be found at: N 0AB C5.DEA E 000 0C.E0E
To help you can get a map and information guide from The James Leal Centre in Ray Park or have a look at the same information online at https://www.redbridge.gov.uk/media/3271/claybury-park-leaflet.pdf
Most of the clues can be solved from the comfort of your armchair using the given link but for one you will have to visit or make an educated guess!
A = The Forsters Woodrush is believed to have first been identiifed in 1795 at point *A* on the Claybury Park Map and Information Leaflet
B = The number of "running machines" in the outdoor gym.
C = Tennis courts originally used by the patients of Claybury Hospital have been overrun by nature, they can be seen today at point *C*on Claybury Park Map
D = A Roman Road runs through the Repton Landscape of Claybury Park - this is marked on the map at point *D* and there is also a plaque visible from the road.
E = Claybury Hall dates from the 18th Century and was converted to private flats in the 1990s - you can see it at point *E* on the map.
Congratulations to anytar and Mr Potty for FTF - quick find and we loved reading your wonderfully detailed log.