Many students, even at A-level standard, seem unable to differentiate the purposes of their writing, such as practical, informative, emotive. I have seen Scientific reports written in the first person in a chatty tone of voice.
All my ten grandchildren spent most of their childhood in Kent and speak RP. When they moved to Yorkshire, they expected to be teased or bullied, but in fact the children they met found their accentless speech exotic - they were often urged at first to 'say something in your posh voice'. Only one girl picked up some local sounds, but she developed a Kiwi accent after two weeks in NZ.
I have never lost my Salford accent, but once I started teaching and lecturing I had to speak clearly to be heard and understood, particularly when I was teaching in Kent. After almost 50 years away from Lancashire, you might expect my accent to have disappeared, but it has only softened.I notice that when I am with my sister, who has always lived within ten miles of Salford, that I revert back to my Northern vowels, quite sub-consciously.
I don't like the Manchester accent, but I could never bring myself to have elocution lessons as it often makes the speaker sound false (cf Thatcher).
It has never held me back in my various careers and when anybody was stupid enough to think they could patronise me I was more than capable of a good put-down. I think it is extremely rude to comment on anybody's accent, unless to pay them a compliment.