TM
The issue with staying with someone is whether you declare it as your main home, From your previous posts you have your own home and are paying Council Tax on that property, so that should not be an issue.
I've looked at several LA sites and they refer to a month, however, I do not believe that this is defined in any legislation or regulation, but I would assume the longer you might stay the less likely the claim that it is not a permanent move will be believed.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
