score:4
This is really borderline. The English in that article you link to is not great, and I would check with the embassy, but my feeling is that what you propose might be technically OK, but it pretty clearly violates the spirit of the rules.
So the basic problem is in the name of the article you link to:
No-Visa Entry Policy for Foreigners in Transit
That is, you need to be in transit through Korea to somewhere else. You aren't, really: you need to claim that you are transiting via Korea to China to qualify, but you are arriving from China, which makes no sense.
That said, section A-ii of the article goes on to say:
A Chinese national who is bound for one of the 30 European countries (Greece, ..., United Kingdom, ...) with an entry visa (including permanent residence status) for entry into the respective country via Korea, or who returns to China via Korea departing from the above-mentioned countries.
Note that, unlike section A-i-(2), a direct flight is explicitly not required, and is in fact impossible for many countries on the allowed list (not only there are no direct Korea-Liechtenstein flights, but the country doesn't even have an airport!). So flying (say) UK-Japan-Korea-China would be totally OK.
In summary, you do not need a direct flight, but you do need to be in transit somewhere else, and you can't really be in transit to the country you just flew in from. If you show up in Korea, with proof of residence in Europe and an onward flight to China, you might be OK... or they might start wondering why this Chinese guy flying in from China is claiming to go to China, and then you'll be in trouble.
Also remember that you need to convince not only the immigration officer, but the airline staff who check your documents. Personally, I would not risk it: just get a Korean visa, it should not be hard since you have a legitimate reason to go.