Inspector Morse tie-ins
Not only is there a John Thaw connection:
Editor Chris Burt ended up being the producer of MORSE and of LEWIS, and writer/dirctor Ted Childs ended up as executive producer of those two series.
Childs was also involved in the production of the SHARPE series; most of those episodes were directed by SWEENEY director Tom Clegg.
And isn't it funny to see Ian Hendry, John Steed's original AVENGERS partner, playing the heavy in episode 1?