The parliament of Northern Ireland also used STV for the same (er, well, inverted) reasons from 1921 until the Unionist majority forced a change to FPTP for most seats in 1929.
More generally, STV was the default choice for assemblies throughout the British Empire (and became known as 'the British system' as a result) from the late 19th century onwards.
It was even agreed on for use in Westminster in 1919 - though only the university seats ever actually used it - making it "more traditional" than the current single-member FPTP system which dates only from 1949. The failure to actually implement it was part of a more general reactionary movement in the aftermath of the war, when Lloyd George's promise of a "land fit for heroes" was thoroughly betrayed.
The Irish system seems to work well, and can be used as a comparator for considering what the UK might look like if that betrayal hadn't happened.
Huh! I didn’t know any of that. I presumed that Stormont elections had always been FPTP and that gerrymandering – particularly in Derry – was the worst abuse of the democratic process in Northern Ireland.
That’s really interesting that the British promoted STV within their sphere of influence and had intended to use it for elections to Westminster. Thanks for the informative comment and useful historical context.