Hi Zammo,
I used to rent out my spare room to students. The rent was inclusive of bills and council tax and all other expenses I incurred as the owner.
I charged 100 a week.
I had maintenance charges, the mortgage, gas and electric. Water rates and council tax. All in my name as I was the owner.
You really must work out the extra expenses and up the payment you are making to the utilities. Have you let the council know you no longer are a single occupancy and now must pay the full tax and not the single rate?
Best of luck.
L.