No, I'm what you call an "educated" Geordie (a rara avis). My accent is more received Oxford pronunciation but I can do the accent if required, like ye knaa warra mean, marra?
I know a Geordie who has been here (Ontario) for about thirty years, and is quite difficult to understand. If he's had a couple of beers you need Bletchley Park to decode him. However, his mother came over here once, and we had no difficulty understanding her at all. She must have been posh like you:)
The trick is, if he's has a couple of beers, then you have a couple of beers and you will understand him no bother. It is not a lack of comprehension which is the problem, merely a lack of beer.
Theoretically, plautus, that sounds plausible; however, going drink for drink with him is the not him most efficacious method of interpreting his rambling. He quite often breaks into "I belong to Glasgee, and...". Quite confusing is he.
If he "belongs te Glasgee" then he is not a Geordie. Stone cold sober, I, a trained linguist cannot understand a Glaswegian. A few beers help, but I suspect that this guy is a renegade Scot pretending to be English.