Since he's British it should be "which rhymes with "arse", glass only rhymes with ass in the north of England and beyond, and even there they'd prefer arse over ass (a turn of phrase I hope to never use or see again!)
Ha yeah I suspect he's aware of the pronunciation differences but kept it that way for simplicity's sake.
Also I'm so sorry but "arse over ass" made me laugh and has kinda imprinted on me, so I'm gonna remember whenever I see "brigandish" in HN comments :-D
Can't get the journalists nowadays.