We have a client who has recently been granted refugee status (Feb). His NASS accommodation has come to an end. He was interviewed for a NINO on the 9th March, and told it will take 4 to 6 weeks go be issued. LA has decided not in priority need.
If he were to find a hostel place, would he be able to claim housing benefit for it to be backdated to the date of claim as he is entitled to a NINO which is being processed?

He should not delay applying for HB, regardless of the processing time for the NINO. In my view he has met the NINO requirements for HB purposes anyway, by applying for one and supplying all necessary info for one to be issued. The short answer to your question is probably that he could NOT rely on getting HB backdated just because he was waiting for NINO - he should apply for HB as soon as starts to be liable for rent somewhere if he wants to be sure of not losing out.