The "late announcement" extending opening hours to 05:00 on Monday means taking officers away from other duties, the National Police Chiefs' Council says.
The 29-year-old was shot while observing rioting in Londonderry in April 2019.
The prime minister's spokesperson says the government is exploring "all possible options in this case".
Two teenage boys convicted of rape had initially been given non-custodial sentences but have since been handed a four year detention.
But the likely next PM says he will stick to Labour's pledges to not raise VAT, income tax or national insurance.