What is this?

[gizmosmama]

Just bought a second hand Maclaren buggy and found this in the basket but can't work out what it is! Any ideas?

How big is it? Is it a cover for the hinge?

I've never seen one, but is it the foot piece for newborn mode? like this?

looks like a hinge cover to me too.

Apparently it's to help stop very small children slipping through the straps.