In reply to summo:
The path ends at the upper falls in your picture. There are some waterfalls marked on the OS higher up, but I'd don't recall any of them being particularly interesting.
When I lived in Middleton, the winters were phenomenally mild, so I didn't look at any of them with a view to climbing potential. The one that is often mentioned as being a possible in a cold winter is White Force, but there are no conditions reports for that.
High Force may be a forlorn hope these days. I suspect the way that the flow is controlled from Cow Green may make a difference. Does anyone know if it has frozen since the reservoir was built? And does Cauldron Snout ever show any potential? It's quite a bit higher.