Yes, technically this is correct and the legislation has not been repealed. I think it highly unlikely that the king would do anything, and if he did I'm unsure the armed forces would follow him against a legally elected parliament.

Futhermore the king is also head of Canada, Australia, and New Zealand; again I find it unlikely that they'd follow him over their govts.

In short there's a bunch of laws that the UK govt. hasn't revoked. Changing unused or unnecessary legislation takes time and there are more important changes to make.