In a similar vein I posted this about six years ago:
In the late 80s I worked for an IT company which was looking at setting up call centre based outsourcing deals (or FM then) in deprived parts of the UK (pre-India days) to milk the Government grants.
They commissioned a firm of occupational psychologists to assess people's reactions to regional accents as part of the planning.
The results were kept fairly quiet but amounted pretty much to people hated most regional male accents but didn't mind some of the female ones.
Nobody liked any Scouse accents.
Brummies of both sexes were regarded as "sounding thick".
Female Scottish, Geordie, Welsh and West Country accents were the most liked.
For what it's worth they started out in the North East.
They didn't look at Home Counties RP as that would have won hands down.