Her accent doesn't sound Swedish.

She studied in a English speaking school in Sweden when she was younger and her mum is English. Plus she's lived in England since marrying her husband since the mid 10's. So that probably is the reason why she doesn't sound very Swedish.

If you learn a second language from a native speaker, while you're young enough, you almost certainly won't have a detectable foreign accent to other native speakers of that language. Numerous studies show that past about age twelve accents become permanent. Well, Ferguson had an English mother, and studied English (no doubt RP British English) in school as well during her early childhood, so it's no wonder that she sounds like native speaker of RP English with this background.