Instead of saying £40k gross, can't you just tell us how much you have coming into the bank each month, OP?
It sounds like saving the odd £20 here and there will be significant for you if going a few hundred overdrawn has caused an issue, so the vague income figure is quite difficult to work on.
We have no idea about your deductions for pensions etc, nor anything you would have coming in as far as child benefit or possibly TCs, etc, so your net income could be anything from, say, £2,250 to £2,800.
Assuming you haven't had household insurance claims, you're paying a lot for yours. We pay less than £200 per year building and contents with full accidental damage cover on a 5-bed with £100k contents including jewellery and watches, etc.
Breakdown cover can be had for less than £30 per year. Have a look at MoneySupermarket - you can do comparisons on there.
The water has to be wrong, somehow. That's 4x what it could be.
Things like boiler cover can be a waste of money when you're paying as much as you are. They don't provide a free new boiler if yours needs replacing and the won't fix faults which are more expensive than the boiler is worth. As someone mentioned, BG do fixed price repairs if you ever need it. You could pocket the monthly payment and then use that money if you ever needed to.
Your mobiles are very expensive but sounds like you're on the case with that.