Want more cash? Not a full time lodger.

I am a teacher working near Clapham Junction. I live in Brighton and need a room to rent for term time. As I work in a private school I get very long holidays which I spend in Brighton. During term time I go home 1 weekend every 3 weeks and then the 1 x week half terms. In all I am in London for 7 months but in Brighton for 5 months. Currently I am staying at a friends flat - I leave at approx 7am and rarely home before 6pm usually 7pm. Alrhough a couple of evenings I have activities I attend so home later still. I'm not someone who "stays at home". I need a place for practical purposes that I will keep clean and tidy. I have lodgers in my house in Brighton so hopefully I am sympathetic to sharing with others.