I agree about the T for Tutbury and S for Stourbridge............... I also didn't know that an asterisk, apparently, indicates made at both factories.
According to Leslie Jackson '20th Century Factory Glass' - p. 249 ..... "1952 - 9: marked with year of production" - but like so many of these backstamps there are variations and anomalies.
I seem to remember Bernard Cavelot saying that the actual dates for the S and T productions were more extensive than the literature suggested.
However, very interesting.
Do you know if the pattern has a name?