FWIW the situation in the UK, that the BBC doesn’t mention, is similarly muddy.

In England and Wales, since 2022, the minimum age is 18. Previously it was 16 with parental consent, which is the situation in (the rather more religious) Northern Ireland.

In Scotland the age is 16 and parental consent is not required.

So, well into the 20th century young English couples would flee across the border and get married there; most famously at Gretna Green, a town just inside the border.

Scottish marriages involving English/Welsh people under 18 are now not legal.