Anyone know what mobiles they're using. Its huge. That's what she said.

Motorola Milestone? Looks very Motorola and from previous episodes they appear to run Android.

Actually quite an outdated phone by Android standards.

might be the camera on it that favoured it?

This was filmed last October

The phone was released in 2009, things move very quickly in the smartphone world. I guess it depends on when the BBC / production company obtained the phones.