Firstly, for my two penneth, I prefer Blencathra to Saddleback. Saddleback, unlike the mountain itself, just doesn't stand out. Saddleback could be the name for any mountain with the appropriate feature. There's only one Blencathra.
Looking it up on Wikipedia, the name Blencathra comes from Cumbric word usage. So Blaen, which would be a bare hill top, and cathrach, a chair. A bare hill top with a chair, which having seen it close up, I can see being appropriate.