It is all conjecture but ....I think in that context it was meant to mean "the real deal" However I think the broadsheet was written by a third party possibly heard or sung in the music hall style, I hasten to add that is only my opinion not a statement of fact

Hence – and I'm speculating here, too – 'ju' potentially a mis-spelling (presumably for phonetic reasons) of 'due', in the sense of 'genuine'?