@izzythepush,
Well, i find that odd. When troops were assembling for King Henry's army to invade France in the early 15th century, those from north of the river found the speech of the Kentish to be almost incomprehensible. An example is the word for egg. Most speakers of English used eye (singular) and eyern (plural), while the people of Kent said egge and egges. There were other differences, too. The word ship meant absolutely nothing to the Kentish, who didn't have that word. This was recorded in correspondence because they were buying their rations from the Kentish, and asking for directions to Rochester ( Hrofescester or Rovescester) and other places where they could "take ship." There was correspondence with the Exchequer because the King was obliged to reimburse the captains for rations for their troops.
It would not surprise me to learn that the people Essex spoke like the Londoners, but it would very much surprise me to learn that the people of Kent did.