I’m from a village in Rotherham. Either people haven’t heard of Rotherham, or it conjures up quite negative connotations, so I tend to say ‘near Sheffield’. If they haven’t heard of that, I say South Yorkshire.
I'm also from Rotherham, but since I've moved to the south of England I tend to say Sheffield. Not many people here really know where Rotherham is, and, as you say, those who have heard of Rotherham seem to have heard of it for bad reasons.
Equally, when I used to speak to people from Rotherham (or Sheffield), if I told them I lived in St Albans, I'd be met with a blank stare. Even Hertfordshire didn't really help so it ended up being 'Just north of London'.
Best one I ever heard was from a former work colleague who was convinced Exeter was in Wales.
When I lived in St Albans, one of my friends from Yorkshire messaged me asking for a small favour. He'd bought something on Ebay from a seller in Bristol, and wondered if I could pop round and pick it up for him to avoid postage costs. He seemed genuinely surprised when I declined on the basis it would take about six hours to get there and back, and cost more in petrol than the postage charge.
Another friend once told me he was visiting my area and suggested meeting for a drink. It turned out he was going to Dover - which in his mind is near London, as is St Albans!
Do people keep their accents after living elsewhere for many years?
I've kept my Rotherham accent despite not living there for 15 years. In fact it seems to have got stronger.
Most people here (in the South of England) can't identify it as a Rotherham accent, or even a Yorkshire accent. It's just generic 'northern'. But I guess I am the same - I can recognise a Scottish accent, but cannot distinguish between the different parts of Scotland.