They haven't been very helpful @philippasmith2. Like @Fire, I'm happy to pay the same each month. This would normally mean being in credit for 6 months, debit for 6 months. They prefer me to be in credit all the time!I'll change suppliers as soon as things calm down and I can find a cheaper fixed deal.
You don't need to pay by DD.I get an email every month requesting the previous months payment, with a link to pay it.