Our Daughter & partner moved in with us recently.Dad & I charge £500.00 per month. Our Daughter & partner are employed & work from home.They have a loft room & have use of a 2nd bedroom to work from. We have upgraded the internet with EE.The lounge,dinning room,kitchen,& bathroom are shared facilities.We live in a old house,the area is not great,but good transport links.We use more energy than average due to poor insulation.We are retired have a net income of £1500.00 net a month.No mortgage or rent.With one pension presently untill early 2026.My daughter & partner are saving up.They earn around £4,500 net a month.Our daughter has mentioned that she thinks £400.00 is the amount that they should pay each month.What are thoughts?