Jon and all his family are Cockneys and I generally don't hear much of the Cockney slang being used when they talk. It's more of a case that they talk very fast, it sounds very agressive, and they use terrible pronounciation and grammar. But Jon tells me this is generally the way Eastenders speak lol.
I do hear a few things thrown in like "'E's 'avin a bubble ain't E?" "'Ave you seen the boat on 'Er"
They also have some strange habits such as "Pie Mash and Liquor" - an interesting concoction of cheap, pies filled with fatty "meat" (I once asked what type of meat it was only to be met with a blank look!), mash potato, and some kind of green slime covering it (liquor).
Not to mention the fish stalls sitting randomly outside pubs where you can come out mid-way through a drinking session and gorge yourself on cockles, whelks and mussels!! Just want I fancy with my glass of rose lol.
Strange things, the Cockneys!