Who portrayed the daleks in the episode with Churchill of Doctor Who?

The Daleks are 'driven' and 'steered' by unknown extras and stage technicians, who sit inside them on narrow benches and propel them along with their feet, looking through tiny narrow eye-slits in the head grilles. It's not an easy job making a Dalek glide smoothly as oppose to jerking with each leg movement, and each Dalek 'driver' needs a lot of practice.

Several anonymous stage-hands took on the job during the episode set in WW2 London, but their identity is unknown. However, if you are keen to find out, The Doctor Who Experience theme centre in Cardiff, South Wales, may have a record of who they were.