David and George
There certainly is some variation in the engraved naming on 18H QSAs. Attached is a pic of part of the edge of one such in my collection. Note that the "H" differs in small detail, for example. Speaking for myself, I would want to do some careful measurement with a good vernier calliper (I don't like the digital type) as part of the edge of Seftons medal does appear a little rounded.