I thought exactly the same. She just doesn't look the part at all. I did spot Chris from Skins as a soldier in the preview.Nice episode overall, the Sontarans are great villains. I would say about the next episode preview:
The Doctor's daughter seems dreadful, she looks like she just dropped out of the cast of Hollyoaks or something XD

That was a reference to The Master. Yana.I'm really looking forward to next weeks...at least now we know what the Face of Boe meant when he said- "You are not alone" and died.