Petrol Pipe Clamp Block,  as per 1st photo but clamps smaller 5/16"OD metal pipe between the 2 halves, which is similar to the original ones in 2nd photo,

For RHD DB2 to DB MkIII models, for LHD DB2 to DB MkIII models you need the Fuel & Brake pipe clamp, similar to this one but with 5/16" & 3/16" pipe holes.

Comes as a pair of halves, a bolt, washer & a plated stiffening plate. (non std / original)

These are specially made for us, not a JMB product.