I seem to be massively in debit as our bills have soared up 3 times the amount agreed… if I switch to a new supplier to cut costs is this payable immediately?

I dont know Bulbs policy but you may not be accepted by a new provider if you have outstanding debt. Best you contact Bulb and/or your planned new provider to discuss.

In addition to the above comments, it would be entirely sensible to work out why your bills have “soared”.

While Bulb have increased prices over the last 12 months, in line with many other suppliers, clearly they have not increased three-fold. There must be some other reason. Either your bills have been based on poor estimates and not actual meter readings, or you really are using more energy than you expect. Switching is not going to help that.

In the first instance, submit current meter readings and check they are entered and used correctly on the PDF bill that is produced each month. Assuming everything is correct, when looking to switch make sure you compare actual energy costs in terms of pence per kWh and standing charges. Ignore any estimates on monthly payment, you need to look purely at the base rate of charge.