DS has moved back home after uni, and his partner is pretty much living with us, as her lodgings don’t allow male visitors. Next academic year she is doing a Masters, and DS has asked if she can officially move in. Putting aside if this a good idea, how would you think about rent? To note, we charge DS £300 p/m at the moment to cover bills, because he doesn’t have a steady income, and because we buy food for both of them. They share the room, have a bathroom to themselves, but we only have a 3 bed London terrace so it’s not luxurious.