True to their word KT sent two engineers round this morning at 09:30 and within minutes I was connected to the internet. It seems to be built into the apartment somehow, there is a network connection in the wall and one lead plugs straight into the computer and the Mac immmediately recognised it, and I was online straight away. No setup, no configuration, so usernames or passwords. This is the way computing should be!
I then got a phone call from someone at KT to say the equipment in the building is better than discussed and cheaper than agreed yesterday so it's 100Mbps and 4,000 Won less. Just this second I got a second call from KT asking if everything was working OK. Very good of them to check.