[Nemo123]

There is some great Telly on Youtube. Generally, it has to hide under a code to evade being taken off by the owners, like the BBC.
My first suggestion is, A Perfect Spy, a 1987 production of a John Le Carre novel, by the BBC.
Look up A P S 101, to see episode one. There are 6 episodes in total. The sequence goes, 101, 102, 103, 201, 202, 301. So it's A P S 101, et cetera.