It is a big qualifier, but not entirely that big. Yes, it would mean that the decision to start the dictatorship was democratic, but you could definitely arrange it so there is no Disabling Act. Don't forget that to pass such an Act would need the Royal Assent, which the government is now in a position to refuse. Yes, that's a breach of constitutional convention, but we'd be well past that point.
So the plan goes something like this: pass the Statute of Proclamations[0], optionally repeal by proclamation section 4 of the Dissolution and Calling of Parliament Act 2022[1] to keep your complaisant Parliament in place indefinitely, optionally make a proclamation preventing them from meeting, definitely refuse Royal Assent to a Disabling Act, and then govern by decree as you please.
Obviously this isn't failsafe in any way. Dictatorships aren't stable just because they've got legal cover, and the politics would need to be carefully managed. But there's nothing in our constitution that would prevent it.
[0]: https://en.m.wikipedia.org/wiki/Proclamation_by_the_Crown_Ac...