I thought it's the Americans who flap their "t/d"s (that's why "pudding" gets transcribed as "purin" in katakana). Not the Brits...
Though admittedly "Baroushippu" does sound closer to both AmE and BrE pronunciations compared to the usual "Batorushippu". And IIRC the Australians flap their "t/d"s too, and Uchida Shuu (Warspite's VA) grew up in Australia, so...
Updated
Bat her sheep!
"Baroshitt" in katakana, with a glottal stop (the 'tt' AKA small っ AKA "choked-off" throat sound) at the end.
TWITCH!!
BAE-tl-SHIP.
"BA-RO-u-SHIppu" in katakana, with "stress" indicated in bolded and larger font.
I wonder if it's some kind of internet slang... ugh... scary...
Those destroyers have no respect for us battleships, you know...