5 June 2017 - Machin 50th Anniversary 1p crimson from prestige book
This gummed stamp with elliptical perforations is a quite different stamp to many of the earlier ones.
This is not a new stamp at SG Concise Catalogue level, but may be recognised in the GB Specialised catalogue.
There have been many different printings of the 1p with elliptical perforations. The picture shows one of the earlier ones on the left, and the latest one on the right.