Polly's surname is never mentioned on-screen, and for a long time there was fan speculation as to what it might be, with a number of suggestions being made. Once it was confirmed, however, that the BBC's audition scripts for the character gave her surname as 'Wright' that became the one that everybody accepted. It's unclear as to whether this ever intended as any more than a place-holder at the time - it's also Barbara's surname, and the two characters are entirely unrelated. Possibly nobody at the BBC took it seriously as a name, but neither did they bother to come up with anything else, so it's what we have.
While her predecessors are mostly sixteen-year old girls, Polly is a grown woman. Assuming she's the same age as Anneke Wills was at the time, she's 24, notably younger than Barbara, and clearly cut from a different mould. She's a secretary from London in 1966, which, at first glance, may not be the most exciting concept ever for a player character. While the ability to brew a nice cup of tea is one that's quite important in British culture, for instance, it's rarely high on most player's wish-lists.
