[ElProximo]

Dialects or 'accents' undoubtedly sound different to my ears as they would to some others.
If I am in the UK long enough I 'tune' to the 'general rules' of pronunciation unique to England for example,
but,
I still find it difficult to discern various regional dialects the further the go from my 'Canadian English' tuning.
Then stranger things begin to happen - for example if I hear an Irish person across the room I will believe I am hearing another Canadian speaking in relative comparison to other regional dialects.
Hira for example sounded (to my ears) exactly the same as any of the Indian girls, raised in Canada that I have known.

Anyways, Irish is by far easiest and then any proper 'BBC all-england' speaking is no problem and any Scotland region closer to 'Queens English' is easier (Inverness for example),
then,
Newcastle not bad at all. Charlie is 'closer' to the way some of our Maritimers talk. I can 'mostly' catch what he says.
Big Problems for my ears:
real working class scouser accents. probably true for most brits too.
No clue wtf anyone with a thick glaswegian accent is saying. I do know that it was wicked sexy whenever Karly got angry but I have no clue what any of them are saying.

David is a 'brummy' sort of regional dialect and I had heard that one before but not in Birmingham where its more of an African sort of accent I always encountered.
Dunno?
This is what I heard David say last night:
"Job inna wot jot dedja bot wot jot!"

I agree with the OP. He ought to always have subtitles and I think it would be hilarious if, at some point, the subtitle writer actually writes "jebba jebba wot jot" for us.
Id laugh and laugh.