[psychphysic]

It's also troubling that it's a crime not to disclose right now.

Disclosing those keys is probably a serious legal decision. The police will copy your entire phone including any nude pics, saucy messages etc.

Given the absurd number of UK police who have gotten in trouble recently for sharing pictures of dead bodies it's understandable you wouldn't want to just give them forever access to that or take a decent period to fully consider.