In reply to Annabel Tall:
I may be jumping the gun here but it seems hard to believe that these were climbers - or at least climbers with any idea of what they were doing and where they were doing it. It immediately seems odd that they were within reach of a Fire Service rescue platform - ie less than the length of a normal climbing rope from the ground - and still required assistance.
The reports suggest that they were brought down from the clifftop above Subsidiary/Canadian Wall, ie on the north side across the road from the parking area under Wind Rock's west face. There's an easy 15m sport route which finishes at a normal lower-off - not the sort of place where one would expect two climbers to get stuck - and the old eponymous Severe that goes to the top; but at about 20m, with some small trees at the top and an easy descent down the back, one would hope that climbers would be able to get themselves down, even at night. There's no mention of injury. It seems more likely that these were people walking on the various paths that weave around between the tiers on that side of the gorge who got a bit lost, found themselves at the top of a cliff some way above the road and had no idea where to go to get down; by contrast a climber who's just climbed up something tends to have a rather better idea of the surrounding terrain.
I hope so, anyway; it would be rather embarrassing otherwise!