I have a Halifax account and sending money back home was a nightmare, epecially with the crappy exchange rates. Nong Hyup trtanfers the money 2X to get to the UK bank. First in Dollars then in pounds.
To send your money to the UK account, you need to call the bank and ask for your bank account code, you will also need the banks address etc. The process in Nong Hyup takes about an hour to get everything setup and once thats done it will be more easier.
I know it might not be possible, but really try to open a KEB account as they are able to convert directly from WON to POUNDS.
If you're far from a KEB, but send money regularly, I would say it might be worth the pain to go to it to open an account--even if it means leaving work early. Just do everything at one shot: open a chequeing account, sign up for Internet banking and Internet overseas remittance, etc. Of course, make sure you bring all the info. with you (passport, ARC, contract, home banking info.).
Keep the NH account for convenience (more NH ATMs around than KEB) and designate your KEB for overseas transfers. Transfer money from your NH account to your KEB whenever you need to send money.