Resident in this case means domiciled here. It includes students, wp holders, agricultural worker, hsmp holders, fiances, spouses, permit free employment, refugee, asylum seeker, and basically everything except visitor.
Having a residence or place to stay abroad does not affect where a person is domiciled. A person's nationality or ILR status has nothing to do with where they are domiciled either.
Just don't confuse it with HMRC's definition of domiciled for tax purposes, which is a different meaning.