Leona
Alexandra
Pixie Lott
Duffy
Eliza Doolittle
Cher Lloyd
Lily Allen (to an extent with her new album)
Ellie Goulding (as above after LMLYD you'd expect her album to smash)
there's probably more but i just can't think of any
The first 6 for sure had massive first era's but they were quickly dropped by brits in their following era's, why?