Latest competitive price quote of Olympus E-3 available in Korea is around 1.42~1.52mil Won, which is between GBP 702~752. (converted at 1 GBP = 2020 Won)
The quote encompasses both on-line and off-line retailers, and should be regarded on an assumption that you suffer from no language barrier in finding, accessing, negotiating with Korean retailers.
Yongsan is famous for their wide-range stockpile and availability, but notorious for their manipulative practice as well. Only well-informed customers are advised to shop there to avoid any rip-off. (the same goes for computers and any other gadgets)
As far as cameras are concerned, there is another market formed around Namdaemun. There could be parallel quotes for the same model - one from the fully licensed, exclusive Korean importer, and the other from, say, 'unlicensed' direct-from-Japanese-wholesale importers. (wouldn't call it a 'black market' as it's not illegal) Both are the same goods (Japanese camera made in sometimes Japan, sometimes China, et el.) but the difference comes with in-country free warranty. Many local customers, however, go for the latter with cheaper price.