My water meter is spinning all the time/ I have received a high water bill

Firstly, check there is no fault with your meter. You can do this by phoning up your water authority. You can also carry out basic testing yourself. When all of the water is off in the property, including any water tanks in the loft, is the water meter still spinning? If so, this would indicate a potential hidden leak within your property. If it does not spin, there is still a possibility you may have an external leak between your stopcock and the mains.