The [MacMillan Dictionary](http://www.macmillandictionary.com/pronunciation/british/balaclava) 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.