Thanks folks for most useful comments!
In the TV context, the Cleganes are proving extremely difficult to nail down. There are a lot of clues that they have retainers (a castle seat, a banner, jousting tournaments, raiding the river lands, torturing people at Harrenhal, etc) but there is a conspicuous absence of a retinue!!! As you say, the guys doing the torturing at Harrenhal look like scum without much in the way of uniform. And to make it more confusing in that scene, The Mountain looks like his wearing a Lanister helm with the same red cloak as Tywin. All very confusing.
I think I might have to hold off on the Cleganes (maybe, but probably not!, it will become clearer in the next series), which is a shame as I wanted a small band of particularly nasty hard cases to do Lanister dirty work (what with the Boltons swinging both ways).
I can't tell you how many video clips, images and forum posts I've looked at to try and solve this conundrum. Ho hum. I'm a bit brain dead at the mo and can't think who they might be substituted with.

Edit: Ogrog: I was writing as you posted and I think you are right about The Mountain not caring about his men's appearance. That said, i can't seem to find any images of them kitted out for fighting - just passing time with torture, etc.