Just realised I am £30 below my overdraft limit, and I have my car ins DD going out tomorrow for £60! Agh!
Now, I've plenty of money in another account. If I go to the bank first thing, and pay in cash - will I be seen as going "over my limit" or incur charges, if I pay the cash in the same day the DD comes out? :-/
Usually the bank will charge you a 'penalty' charge for having "insufficient funds to cover the DD". However, if you go in tomorrow and explain that you have made an honest mistake, and you have more than enough funds in another account they may give you a refund.
However, this is never guaranteed of course with banks in the mood they are, and as I have bitter experience of with Abbey National you may have to protest quite loadly to obtain the refund. Indeed with them I had to call their main centre to obtain any refunds as the branch was "not authorized" to do so.

As a matter of interest I secured a £2,000 settlement for "Penalty Charges" from the said bank after I sent my own 'legal' letters to them and took them to the small claims court, where in the end they backed down and paid me in full my claim before the hearing.

I trust your small mistake will be sypathetically dealt with James.

PS my banks appear to 'balance' debits / credits electronically at midnight as the DD / SO is scheduled to leave your account. Insufficient funds at this moment will result in a charge.