I currently have two lodgers living with me in my house under lodger agreements. The rooms are for single occupancy only and I have home insurance which covers two lodgers. My written agreement with both lodgers is that they are allowed guests to stay in their room for a couple of nights a week. I'm aware that having more two lodgers living in a household would turn it into an HMO (house with multiple occupancy). Now, if one of the lodgers' boyfriends comes to stay, how many days of him being here would mean they're actually living here rather than just being a guest? a week, two weeks, a month?