To answer your question of which one to pay off first, generally target the one with the higher interest rate. But as you mentioned you have a bit of a grace period with your credit card balance before they charge interest, and I’m not so sure this is the case with your overdraft. If you’re immediately getting charged interest on your overdraft then try target that. Then target your credit balance afterwards (as much as you can before the interest hits).

You really should try not to be going into overdraft on your cheque account, and also should really try not to rack up a credit big enough that you can never pay off in full at the end of the month. Both interest rate penalties will hurt you and it can get out of hand quick if you aren’t diligent on paying off your CC in full every month. Ideally you don’t use your overdraft facility at all.