Linguists have noted the existence of pronunciations of the "mouth" diphthong with a "fronted" offglide at the end (one that sounds comparatively less like a "w" sound and more like a "y" sound) in several distinct accents of English.
The linguist John Wells wrote two blog posts in 2010 about the alleged usage of a pronunciation similar to this by Queen Elizabeth II:
Wells observes that even when fronting is not present, the vowel may not be very rounded. A blog post by the linguist Geoff Lindsay transcribes a pronunciation of this diphthong in Charles's speech as [ɐɤ] ("The King’s Speech: Charles III’s RP accent", Speech Talk blog, September 15, 2022)
More relevantly though to your example of Jim Browning, Wells also has a page titled "links to recordings of English accents and dialects" for his book Accents of English with some descriptions of the recordings, including the following note about Northern Ireland:
Among the special Ulster characteristics are a MOUTH diphthong which ends in a central, usually unrounded, quality, [ʌɨ]
That supports Stephen Manistre's answer ("It is a common pronunciation in the North of Ireland"), which a moderator deleted and converted to a comment.
(The audio on that page only works on some browsers. Wells advises Internet Explorer.)