judging from what I’ve seen of Peter Davison that comment is absolutely his humour. And tbh it doesn’t seem too far from Georgia and David’s humour either. I bet they found it funny (especially since he keeps repeating the story, I’m guessing it went down alright)
Headcanon but I bet Peter loves teasing his son-in-law, he makes for a great target. He's a big nerdy fanboy who's also v sweet and as someone who says Peter is his favourite doctor (because "he doesn't want to be kicked out of the family") and who just had to fall in love with his daughter, he is so at the mercy of his father-in-law.
I bet David giggles a lot when Peter teases him and Georgia, I'd love to hear how those conversations go down even now lol