I saw plenty of crew coming and going: Peter Bennett, Danny Hargreaves, main wardrobe and makeup people, sound and camera guys. It looked like the main unit, but couldn't be sure.
I saw two supporting actresses in matching white blouses, black trousers, chunky black shoes. One was blonde, one with black hair. I couldn't recognise either of them. I was reminded of the two who left Tredegar House with coats over their heads, white labcoats, black trousers and chunky shoes. Then again, since they're supporting artists and probably not well-known, why hide their faces? I was told David Tennant wasn't there, but couldn't verify that either way.
There was definitely effects work going on. A greenscreen went in, as did the reflective globe they use for CGI reference.
Special thanx to Alun.Vega for the photographs and set report!