How to practically get one-bedroom LHA rate due to residence in hostel/refuge/safehouse

I was wondering about what the actual process is for getting the one-bedroom rate of the Local Housing Allowance for someone under 35 who has had 3+ months of residence in a hostel/refuge? Is evidence of residence of this type of accommodation to be submitted to Universal Credit (in both cases that’s who needs to pay the rent via housing element) or does it also have to be agreed by the council’s housing benefit team, even if it’s not housing benefit paying?

For one client it was a homeless hostel that definitely obviously fits the criteria, and for another client, she spent more than 3 months in an independent safe house provided to survivors of modern slavery. I was thinking of trying to argue that the latter also counts as a hostel/refuge, given that it meets all the other criteria (shared kitchen facilities / provision of food, and that she received support and resettlement services whilst in the safehouse also).