Summer Lets

Tenancy Types and Management

I have a small student hall where I offer 42 week tenancies. I would like to offer the accommodation during the summer months to students (not necessarily those who are currently in occupation). I understand that if I offer a fixed term AST for the 9 weeks available for the lettings, I could find myself in bother if the student exercised their right to stay for 6 months. I also recall from an RLA course some years ago that a licence to occupy does not have a legal standing. Does anyone have any idea how I can use these 'empty' weeks to raise some income without being caught out.