Moving home

I have moved house and can:t enter meter readings as it says my account has been closed and I can’t see anywhere to change my details

If you advised Bulb you were leaving your old house then that account would be closed. If you have not registered the new house then Best you contact Bulb on Monday to advise.
It may be possible to register as a switch / new customer to get it logged on their system.
I wouldn’t worry though as Bulb will sort it out for you.