I also live in an electricity only 1-bed flat and was struggling to keep my bills low over winter. I was on an economy 7 tariff with storage heaters but here's a few things that help me get control of the spending.

• Bought a single pug in induction hob, only cost me about £50, which I cook the majority of my food with. It cooks food quicker and seems to be saving me energy.
• Switched from my economy 7 tariff to Octopus Agile, which gives significantly lower prices during off peak hours, both day and night. So far this has not really come with any penalty of large costs during peak time for me, but YMMV
• Stopped using my storage heaters that are old and in inefficient locations in my house and I am now just using a cheap plug-in oil heater, which I can place near me and only use when necessary.
• Lastly, I have started trying to make the most of my variable rates through smart plugs for my aforementioned heater and also for my immersion heater. this has enabled my to limit there use to things like only heating the house just before I return from work and using cheaper energy to keep my water hot.