A different woman, somewhat more important than Liz Truss, but also with the given name Elizabeth. She was roughly the same age as my (dead) grandmother and they had roughly the same notional military job during WW2, driving a truck.
GP means Queen Elizabeth II, it's an annoying antimonarchist trope of being coy about the most obvious descriptors and using generics because 'they're just like the rest of us' etc.
I don't think I've ever been called "antimonarchist" before. I think a (constitutional) monarchy is a very good solution to a big real problem if it's available and so the UK is in an enviable position in this regard.