Stansted! They are NOT Essex accents at all. What you are hearing is Thames Estuary derived from East London. After London was blitzed, 1000s of families were relocated in Essex - mine included.

The Essex accent is very similar to the Suffolk accent but even that and the Norfolk accent are in decline.

Boo-i-ful way o' tolk'in hhev they ol' bhoys garrt, 'bor