1. Billie Piper in The Shadow In The North, playing a Victorian Era sleuth named Sally Lockhart. 2007. Cast includes Matt Smith (3 years before becoming the Doctor, but around the same times as his hook-up with Billie in Secret Diary of a call girl.) Jared Harris, being VERY Moriarty-ish AND Julian Rhind Tutt, who plays Angus McCain in The Hour, very young and nearly unrecognizable as a sort of fake vampire magician who is apparently irresistible to women, aside from Billie.
If you're a Matt and or Billie fan, you've got to check this out for the Doctor meets Rose element, which is pretty impossible to ignore.
Bonus points for the Alan Cumming Masterpiece Mystery introduction.
2. We went back to the first episode of Foyle's War and who should turn up, but an impossibly young James McAvoy? Also, whereas the first time around in 2002, long before I became a UK Telly maven, the solution to the murder was actually a surprise, now it was immediately obvious who the killer was because it was the actor who played Peter Kingdom's sleazy brother and also the baddie in a Midsomer Murders that I saw just last week.