Re: overdraft
Are you suggesting that the bank will cut your approved OD limit each month? I don't think this would work - firstly the bank won't be too keen about having to get one of their people to carry out a transaction on your account each month to reduce the limit, and I doubt if they have an automated way of doing this. Secondly, you can still breach your approved limit - they will just start hitting you for extra 'referral fees' and interest charges. So it won't really solve your problem.
The real solution lies in managing your spend to spend less and pay back the debt each month.