Buying watch series 4 in Korea to use in UK

I shall be in Seoul in South Korea on 2nd November which is also the release date of the Series 4 Apple Watch. Can I still use the watch ok in the UK if I buy in Korea, or are the models

different in any way? The model appears to be the same in UK and Korea (model A2008 for 44mm). I want to get cellular black stainless steel model, so will this function fully in the UK or is there a slight variation in Korean models? mostly looking for confirmation of Apple Pay use, possibly setting up for cellular later on and full warranty coverage (with Apple care + purchase). Other option is to try in Japan as I shall be there for a day, but Would prefer Korean purchase as availability is more likely

i should point out the reason to get in Korea or Japan is cost and availability