Hi,
Both my account for fresh water (you) and for waste water (southern water) state they use estimates for the meter. 

I believe the meter was checked automatically when I signed up, has this changed?
The meter is behind a door with a code lock, containing all the meters for the flat block. Can I have this code to check the meter?
Can the meter reading be shared with southern water?

My bill recently jumped hugely, my water use hasn’t changed. Is there a possible leak affecting everything?

My current combined water bill seems to be £80/month (both companies combined) which seems excessive for a single occupant who was not physically at the flat for at least 4 weeks of the last 3 months.