I successfully bid for this image of an ‘unknown’ member of 87th. There was no provenance unfortunately, apart from it coming from a house clearance in Rhyl (no other 87th linked items).
A fellow Twitter User thinks the inscription says “H Baltham”. There is a service number anyway, 4126766 which I can use for the MoD form.
The photo is likely 1940-41 before the regiment moved back to Devon.
The motorcycle appears to be a Norton 16H (with thanks to @milmodelscene).
87th Anti-Tank Regiment, Royal Artillery (7th Devons) 