Quick note re: the casting of Alex Kingston on Arrow—they’ve also cast Colin Salmon, who played Dr. Moon in Silence in the Library/Forest of the Dead, as Oliver’s stepfather, Walter. Fans for sure!
I also just remembered, on the note of Arrow being a fun little Doctor Who reunion, Ben Browder (Farscape, SG1) who was also Isaac in “A Town Called Mercy” was in Arrow aswell; in “Trust But Verify”. Oh and fun fact that may not be apparent to anyone who doesn’t live here, but Vancouver, where Arrow is filmed, was also where the 1996 Doctor Who special featuring Paul McGann was filmed.