I have some doubts as to what this is. It is quite common at the top of the Glade, mixed with Creeping Cinquefoil.

It has only four petals, but is not Tormentil Potentilla erecta, it also has some leaves with five leaflets. There are two possibilities: Trailing Tormentil Potentilla anglica or a hybrid between Tormentil and Creeping Cinquefoil - P. x mixta (=italica). This is most likely.

Gulielma Lister recorded P. anglica from Wanstead Park in 1941.