You can extend it by trying to find the summit of Kinder Scout once up on the plateau. Its marked by an OS trig point and we have to take their word for it that its the highest point! :-)
Steve / Dave, That trig point's not actually at the highest point. The high spot is at SK 08522 87527 and it's pretty tricky to find and easiest to access (IME) from from the Pym Chair area. (TBH it's not worth the effort though, the trig is a much nicer spot) The real summit sports a couple of rocks on a mound that's barely discernibly higher than the surrounding peat.