angry of farlington:
Regarding point (2) that depends on the terms and conditions for the particular tariff and the attitide of the supplier to the request. Have you asked?
Regarding point (1), possibly less occasions to incur charges but at the expense of the payment being much larger and particularly so in winter. Only you can decide whether you can manage that better than fixed monthly direct debits.
Is it possible to make a small adjustment to the Direct Debit collection date to lessen the problem?
Possibly the bank, I assume bank adviser, was trying to soothe your anger, but perhaps the advice is a bit simplistic.