Our night saving tariff starts automatically at aprox 1pm till aprox 5or6 in the morning. can this changed?
Probably not - ‘dumb dual tariffs meters’ tend to have the hours ‘hard coded’ into them and are set to help ‘balance the national grid’ (so it’s common for all meters in a region to be set to the same time - see https://customerservices.npower.com/app/answers/detail/a_id/179/~/what-are-the-economy-7-peak-and-off-peak-periods%3F by another supplier).
I believe ‘smart dual tariff meters’ are able to have the times changed, but again I would suspect Bulb would be loath to do so as they’ll probably need permission from the National Grid.
If Economy 7 isn’t working out for you, you can change to a standard ‘single rate’ meter for £120 https://help.bulb.co.uk/hc/en-us/articles/115003610092-Can-I-change-to-or-from-an-Economy-7-meter- , but if you wait until sometime next year when Bulb is rolling out smart meters, you’ll be able to swap to a smart meter free of charge and these can be set on whichever tariff is possible (including a special ‘Smart Tariff’ https://bulb.co.uk/smart/ ).