[Argyess]

I turn into a broken record on this, but worth remembering that the mechanical symbols of old tied up a studio (Pres B) so the limited window that they were used for was more out of necessity than choice.

That's true, although the practice of airing the Christmas ident for just 3 days (with the occasional extension to 4 or 5 days in the years when there were Bank Holidays in lieu) would remain in place all the way up to 1999, long after the mechanical models had ceased to be used.