It is hard to imagine a less fashionable sitcom than Mrs. Brown’s Boys, Brendan O’Carroll’s cash-spewing granny-drag comedy in which he plays the foul-mouthed matriarch at its centre. Based on the act O’Carroll and various family members developed on stage over years of touring, and co-developed by RTE and BBC Scotland, the show is powered by the comic appeal of a stocky man in a dinner lady’s vest pottering about sets, mugging for the audience, laughing at his own jokes and spitting out ‘fecks’ like punctuation. Trading on shoe-worn sitcom set-ups, Mammy-knows-best nostalgia and gags so broad a rookie stormtrooper…