This text is 'super-annoying', as you say. Don't worry about it.
It isn't a real story. Someone has written this text deliberately BECAUSE it's full of language that you wouldn't be expected to understand. The writer is trying to confuse you. They have taken a list of examples of working class (mainly) London slang, and invented an totally artificial piece of text containing as many of them as they could possibly cram into six sentences.
Basically, the writer is saying two things:
* Hey, isn't British English weird and funny?
* Hey, aren't I clever? I've managed to use every "Britishism" I can think of in only six sentences!
It doesn't even sound natural. For example, the last comment means "What nonsense!", in the sense of "What a lot of lies", which isn't even relevant to the rest of the story. Nobody would really say "What a load of bollocks" at the end of this story. It doesn't make sense. The writer just wanted to tick this amusing comment off their list of "funny things that Brits say".
And by "funny", the writer means "things which Americans don't say". For example, the writer cleverly slipped in the word "fortnight", which is something that Americans see as typically British. I even suspect that this was written by American. It's the equivalent of a British person trying to write cowboy dialogue full of 'Howdy pardner' and suchlike.
If you're planning to spend your life watching soap operas and old cop shows set in London's East End, you might find one or two of these phrases useful to aid your comprehension of the (not entirely natural) dialogue. Otherwise, it's a complete waste of your time.