Pronunciation

On TV this morning, on the programme 'Wanted Down Under', there was a couple from Essex, who were thinking of going to Western Australia.

He repeatedly referred to the City as 'Perf'.

How annoying is that? 

I see it as a lazy habit from childhood, where it's easier to say than 'Perth'. Why hasn't anyone told him that he is pronouncing words incorrectly though?

Referring to 'Grandma' as 'Nan' is an equally annoying habit.......