[i.h]

Firstly remember that back then they were more regional magazine shows than full news bulletins. This goes for both ITV and BBC. 

Secondly, the name Calendar wasn't really unusual back then, Westwards equivalent was 'Diary', Borders was 'Lookaround' Southern had 'Day by Day', Thames had 'Tonight' etc

It's just Calendar is the only one left

although you could argue it persisted into the 2000s with some other regions. "Westcountry Live" isn't the most cryptic name, but IMO it also doesn't immediately scream news. (IIRC they originally also had shorter bulletins called "Westcountry Latest", which is more newsy)