Leaden Boot went via Alstonefield, Ilam, Calton, Grindon, Ecton, Sheen, Pilsbury, Hartington Alstonefield.
It was a very "technical" course:
Altitude change was +1420m / -1420m, so very hilly (Ben Nevis, for comparison, is 1344m).
Steep steps around Ilam / Doveholes.
When it wasnt uphill or downhill (see picture), there was a 45degree camber, left or right, so very tough on the ankles.
It was very wet and very windy. Much of the course was slippy grass, slippy rocks or slippy cowsh!t.
Navigation was by written instructions, but you also could copy displayed route onto your own map on the day, no pre-study of route.
One of the woodland paths was very rocky and also had low fallen trees across the path at head height. (I saw all except one....and then I saw stars...)
There were numerous gates and cattlegrids and 74 stiles of assorted variety and height. (At 10 seconds per stile, thats 12 added minutes)
On the positive side, one can easily finish in the top 100, it was cheap (£10), and this included the pie and peas at the end.
All in all, a "challenging" experience. ie horrible, never to be repeated.
I would only recommend this to people I dont like, or those fixated on PBs as it will easily add 2hours to expected times.

Even most hardened fell runners took >5hrs.