Could be juvenile male, still with dorsal stripe.
Slow worm are often found in spring, summer and autumn under refugia installed by the Surrey Amphibian and Reptile Group. Dark flanks and dorsal stripe indicate the female.
This photograph was not taken at Sable Wood, but sand lizards are present in the adjacent Bourne Wood (Forestry Commission).
Silver on left is female - dark flanks and dorsal stripe. Brown on right could be male - flanks similar to dorsal surface.
Silver on left is female - dark flanks and dorsal stripe. Brown on right could be male - flanks similar to dorsal surface.