Wow! Greetings fellow Gloucesterite!
heh heh. That's a trick I've missed. Don't think mine expires for a good while now.
My parents had two older friends, a couple, who were "real Gloucester". (We kids called them uncle and auntie, as you did in those days). He especially used to pronounce it "Glorstur" with a very long "o".
My parents (who were northerners) didn't allow me to pick up the full accent (and we moved when I was 11), but I think I probably had a slightly rhotic "r" for a while.