I can't say anything about the parallels to what Jason Isaacs' accent communicates as far as British class or geographical implications, but for Zhukov himself - who you can listen to giving an interview later in life here](https://www.youtube.com/watch?v=wATbalnQnzk) - he came from poverty, something that he liked to play up considerably in his memoirs for perhaps obvious political reasons, perhaps to accomodate the fact that his father, although quite poor, was a tradesman rather than a peasant laborer. In any case, he grew up in the town of Strelkovka, although it is since renamed 'Zhukov' in recognition of its most famous son, which is roughly 80 miles to the southwest of Moscow. His father was twice orphaned, so to speak, first adopted at the age of two by Anna Zhukova, a widow, and then losing his adoptive mother at the age of 8, after which he was apprenticed to a cobbler. He worked in Moscow for a time, but was exiled from the city in the wake of the 1905 Revolution, returning to the town where the rest of his family was, and being quite poor at his job it would seem, as the family continued to subsist in stark poverty, which he plays up in his memoirs.

His mother is generally portrayed as a simple peasant woman, but he family over all had a bit more success, as her brother ran a successful furrier shop in Moscow, to which Zhukov was apprenticed. Zhukov describes his mother and uncle as 'growing up in poverty' and uncle Mikhail building up the business through his own hard work (and 'mercilessly fleecing' his rich clientele'). At age 17 when war broke out, Zhukov was likely on the path to entering the ranks of the petty bourgeois in Moscow, working as a supervisor for his uncle and dreaming of his own shop, had the conflict not steered him on a different path, being drafted in the summer of 1915, and entering into a military career instead.

So anyways, hopefully that sets up a bit of background for Zhukov himself - I talk more about his biography here - and someone with a better sense of what 'a thick Northern England accent' implies can suss out some parallel meaning.