I don't understand the problem with how Halifax do things. If you know that the DD will still come out, even if you make an extra payment, you just take the amount of the DD into account when working out what you can afford to pay.
You could set up a standing order and adjust it every few months as the DD drops, or you could just make a manual faster payment when you get your statement/get paid. Hardly 'supremely unhelpful' unless very basic primary school maths is beyond your capabilities.
I can't afford to overpay on the minimum more than a tiny bit really
But the point is that you can afford the current minimum plus a tiny bit. Left to it's own devices a credit card set to take the minimum each month of 1% of the balance will take about 20 years to clear.
Set a fixed payment of today's minimum, plus even £5 or £10 and it will be gone in about 3 year and you'll pay much less interest.
One reason why credit cards got people into this sort of long term problem was the dropping of the minimum repayment. When I got my first credit card 20+ years ago, the minimum repayment was 5% of the balance, so larger, so took more off the balance.
If you were only paying the minimum, the amount of debt you were in when the minimum became unaffordable, which is often the first time that someone realises they have a problem, is a fifth of what it is with current credit cards with 1% minimums (although I think it's now 1% plus any interest and charges, but there was a point a few years ago when it was simply 1% and often the minimum wasn't even clearing the interest each month and people's credit card balances were still growing, even with no additional spending, so I think the regulators told issuers that was unacceptable and minimums had to cover the interest plus some of the balance).
So say you can afford £300 pm and the minimum payment is 5%, that's a debt of £6000, but if the minimum is 1% and you start to get into trouble when this gets to £300, that's a debt of £30k
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