Adam P,
I did notice the date quoted above, and was hoping you would pick up on it too.
Unfortunately I am one of those people who sometimes 'can't let sleeping dogs lie.' I have continued to search for myself, for more information.
I seems though, from what Ivo says, that it is more-than-likely to be dated to the late 60's, early 70's, which would account for the fantastic condition of most of these pieces.