Each one is unique, Christine....
I've been thinking somebody could base an amazing collection of Mdina around one shape alone - especially if they concentrated on something like this!
I've just clambered up a ladder and got mine down. They're both dated 1975, one is signed by Eric Dobson.
I have no way of substantiating this, but I have a personal suspicion this might be an Eric Dobson design - some of the two-tone stuff is absolutely fabulous, and matches these bottles, but some seems to be far simpler - and later, (mostly sort of "hat" shaped vases, with "helter-skelter" clear strapping around them.)
The fact that I've seen mid-'70s dates on them, all post-Harris, is all I have to go on, really.