United Utilities can only bill you for water charges so forget about them and heating.
Whilst they are responsible for getting electricity to your home and possibly your electric metering, they are not an electricity supplier so won't bill you for electricity. Therefore, it is pointless providing them with any electricity meter readings - they need to go to your supplier.
On the water side, perhaps you have an agreed weekly or monthly amount. With a current water meter reading you may owe them some money or they may owe you some.
An annual bill should bring your water account up to date.