I was wrong don’t give your landlord your last bill give him ALL your power bills and ask to be re-compensated which over the last 12 months should be about $5,000.
You do not pay for electricity and gas used in common areas or adjoining premises and if you are being charged you can negotiate with the landlord for compensation. If this fails, apply to the NSW Civil and Administrative Tribunal (NCAT) for orders that the landlord carry out repairs in order to stop this from continuing and for compensation. Contact your local Tenants Advice and Advocacy Service (TAAS) for help.
https://www.tenants.org.au/factsheet-23-utilities
However you will need to engage an electrician to provide you written proof of what you state but this shouldn’t cost more than $200 at most and you should get this back when you win.
see here also (this wouldn’t cut and paste) UTILITIES
https://www.tenantsrights.org.au/Publications_Archive/
The fact is the meter has to be an accurate measure of YOUR usage which your meter is not and if you are not on off peak power for water heating your landlord is liable for ALL your power bills until the meter does record only your usage. If you are on off peak power he is only liable for the off peak cost.