Yes, Andy is quite right. The SI puppet of QE the QM looked remarkably like Beryl Reid. Strangely though, Beryl was not a Brummie. She was brought up in Manchester and did not have a natural Brummie accent. However in the 1950s she won a role in the very popular radio show "Educating Archie". She played "Marlene", a dreadful Birmingham schoolgirl with giant earrings who sported a very thick Brummie accent. Beryl went on to use this accent in a number of roles.
By the way, for younger viewers, "Archie" who was being educated in the show was a ventriloquist's dummy, the vent being Peter Brough. Yes that's right, a ventriloquist act on the radio !!! Archie was a sort of young, upper class twit who wore a broad-striped blazer and referred to his operator as "Brough". Various guests took part in the show among whom were Max Bygraves, Hattie Jacques and Julie Andrews.