I think if there's any crumb of comfort is that they snubbed Geri Halliwell back in 2000 for Beth Orton despite the Spice Girls (minus Geri Halliwell) getting the 'Outstanding Achievement to british Music'award. That however as I said was
back in 2000.
Kate Nash is doing fairly OK in the US but mostly thanks to
Foundations being used on a few soundtracks. I'd find it very strange if they were to snub Leona Lewis for Best British Female though.