1965 Guard Daleks
These Daleks could be seen guarding doors/entrances to the main control centre in the Dalek time ship in Episode 3 of The Chase. Different variants were later seen on the planet Mechanus searching for the Doctor in Episode 5 of The Chase.
Behind the scenes
These Daleks were not designed or supposed to look any different to the others. They were extra Dalek props hired by the BBC from the first Dalek Movie. Their bases were removed in Episode 3 to make them fit in more as they would have appeared taller than the others, their lights were also replaced for the same scene although the original head lights were reinstated for Episode 5. They can easily be spotted because of the darker head dome and lack of slats.