I've started listening to Series 6, and it provided one of the best quotes ever. It is VERY spoilerific, so I'm hiding it behind this cut, so if you look, that's your fault.
Cut hiding spoilers! You've been warned!
Leela: There is a saying, that you only ever meet a Dalek once.
Jevon: Except you three.
Romana: We were lucky. Back then, we had the Doctor.
One thing I've really liked about Gallifrey is that they reference the Doctor very sparingly. They don't use the Doctor as fan service; they instead rely on their own strong cast and storylines to build their own unique brand and following. I remember something that Neil Gaiman said once about the Sandman series. He said that when he wrote it, he imagined that the Endless were the celebrities, and that if he wanted one to appear in a story, he had to pay them a million dollars for each appearance. That way, he kept them special, while also forcing himself to improve the quality of the base stories and not rely on the Endless to keep the audience engaged. Gallifrey does the same thing. I think they've mentioned the Doctor twice in total so far. Well, three times...
Okay, a few more spoilers, though nothing you wouldn't know if you read the Big Finish teaser synopses...
The Doctor does appear once. In Series 4, when Romana and the gang are exploring alternate Gallifreys, and they encounter the Doctor on one of them. Colin Baker is awesomely exquisite in this episode, and the entire series is worth it for this alone.