Just got back from an LHR-ICN trip in Y. Some thoughts:

The flights were on different aircraft: LHR-ICN had the new VOD system, which works quite well (though I couldn't figure out how to get back to the start of a movie -- I think you have to press 'stop' twice). On the return, it was the more standard 9-channel system, on a 2-hour loop.

Unfortunately, it didn't matter how good the technology was, the films were pretty rubbish.

Not that that mattered - as I slept for 6 hours on the way out, and 7 on the way back ^ ^ ^ .

Meals are very good -- someone should let the non-Asian airlines know that steamed rice works much better as a starch than pasta (which just disintegrates), and that red meat (beef) always works better than chicken or fish (which gets dried out). And meals with no dairy products means that the plane smells nicer after 12 hours ^

Service was generally good, though they didn't seem to bring round drinks very often.

Check-in at LHR is a bit of a disaster as there are only 3 agents dealing with all economy/non-*G passengers for a 777. There is no online check-in.

Seoul airport is a delight. Fast immigration (helps being a non-Korean on a Korean carrier!), fast bag delivery, spacious terminal. Busses to city-centre hotels are comfortable (more legroom than in a taxi) and quite cheap (13,000 KRW each-way), and go about 4 times/hour.

On departures side, we also found free WiFi leaking from the Asiana F- and C- lounges (anywhere round gate 12).

Oh, and carry-on rules from ICN are the same as in the US i.e. one carry-on plus one personal item (not the LHR "one carry-on plus nothing" rule).