if she doesnt satisfy the criteria for HB due to fear of violence then her HB ends at the old address at the point she moves out, if she does then it ends at the point she decided not to return, plus a potential 4 week notice period of HB.
If she has a rent free period, then you'll need a new claim.
And clearly yu'll need to look at commercial arrangement (gas certs, insurance, etc) before considering the new claim.
