Ah ha, The age old question.
I've never lived in Southwell, but was born and bread in Clifton, Nottingham. My understanding is that people in Southwell call it South-well. People outside call it Suth-ull.
Personally it is South-well.
However people in Blidworth (about 7 miles away, where I now live) pronounce it Bild-uth and Rainworth (2 miles from Blidworth), Rain-uth.
Nottingham, as most places, has grown out of swallowing up smaller villages and these very local dialects still exist today.
Best Advice, is to say it however you like, we tend to respond anyway.
