The hyphenation isn't actually the spelling of the word, but the separation of the word into individual syllables for the pronunciation.

Because the style of separation of syllables isn't based on UK-English, or US-English, none of the above is "correct UK-English." They're just different systems of representing pronunciation.

The MacMillan Dictionary provides an audio file of both the British, and the American pronunciation.

In my opinion, the first hyphenation, the Merriam-Webster hyphenation is more of the American pronunciation style, whereas the British pronunciation is closer to the hyphenation style of the Oxford Advanced Learner's Dictionary.

Thus, out of the two examples you gave, the second is correct UK-English, while the first is correct US-English.