You can't go back from RAS to Rent Supplement. It would be seen as giving up local authority housing, which disqualifies persons from Rent Supplement.
Sorry, yankinlk, I was reading the RAS procedures from the Co Co where it said that they found the properties rather than the tenants. I think that this is how it's supposed to work, but obviously there have been other procedures in place to try to get the scheme up and running.
And yes, the plan is for all long-term housing needs to be dealt with by the CoCos either by RAS, Social Housing, or the like, and away from Rent Supplement which was designed as a short-term housing support.