They are no odds. Some do, some don't, even within the same bank. It's a totally random process.
Look at it this way: If you start contesting, as long as the amount is in dispute, they shouldn't be able to close you down. If they demand the money back, treat them as you would any other creditor, and say you'll repay them xxx (affordable amount) per month until debt is paid off. Insist they freeze
interest
while this is ongoing. Don't forget they have a duty to try not to take you to court, so if you make an offer of repayment, you are fulfilling your obligation of reasonableness.
Of course, once you get your charges back, you can then pay them off.
Alternatively, if the charges are more or less equal to the o/d, you could try to negotiate one against the other, they get rid of the o/d, you go elsewhere.
Open a
parachute account
now, before they mess your credit rating, though, just in case they do that.