How come people from Leeds can have vastly different accents?

ie: Scary Spice has a distinctive Leeds accent, yet Julian Barratt from Mighty Boosh is from Leeds & I umed he was from London or something as I couldn't detect any "Leedish" about his accent. Does this mean the broad, distinctive accents are "working cl" people & the middle of the road ones are people from middle/upper cl Leeds? I know someone from a housing estate in Leeds & her accent is even more broad & pronounced than Scary Spice so I am uming it is a "cl" thing? Excuse my ignorance, I'm not from the UK & I don't mean to offend by referring to people by "cl"!