Switching to direct debit from PAYG for Energy

They'll all take you on direct debit, as long as you are classed as credit worthy. But if you are looking to change supplier as well, then switch to Octopus, you can go through the refer all scheme on here. You'll get a £50 bonus, and if you join their Tracker tariff you'll pay around a third less for your energy. They'll do direct debit, and in fact after a couple of months you can adjust it to a level you can afford, or are more comfortable with

If you're in a hurry to switch, I can say from experience that Ecotricity and E.On both have very short waits for a meter installer to come out. Both have prepayment and postpayment options available. And both support smart metering so will be able to switch you from one to the other easily if you already have a SMETS2 Meter or will let them install one.

I didn't come from prepayment, but Ecotricity got me booked in to rip out my old SMETS1 Meter and replace it with a second generation one within about 2 weeks of joining them and did so without any fees or hassle. And one of my friends joined E.On Next on a tariff where a smart meter was required. They were all sorted within the space of the month too.

Just make sure they don't have a reason to not let you switch from prepayment. If you're bankrupt or have terrible credit with a recent history of bad debt for example then I don't think many companies would be interested in switching you over.