Can't argue; 'telly' is British and 'informal' (ie slang) for 'television', according to the COD. But the same dictionary gives 'snit' (which was in the same puzzle) as 'N. American, informal' for 'a fit of pique'. It's not a word that most Brits would know and use. Having said that, 'snit' seems to come in one of the Chi puzzles nearly every other day, so it's very familiar to regular solvers.
Incidentally, I was one word short of a rosette in the 'loneliest' game; I played 'snit' but missed .......'tellies'! And I'm a Brit!
MK