After the TARDIS is uncovered, as the Dalek says "Destroy the enemy time machine", one Dalek lifts up a few inches, because the operators inside had to carry the Dalek "shells" rather than riding inside a shell mounted on a tricycle, as the mounted Daleks could not be used on the sand.
While fleeing the mire beast Barbara knocks over a stalagmite, revealing it to be made of polystyrene.