This rather tall wall is in Grisdale. I noticed this one as I returned from a strole up Helvellyin on my way back to Patterdale.
I can't recall the hight but judging from my mountaineering rucksac (40ltr) I'd guess it must be around 10 to 12 ft tall.
This splendid wall must be passed by thousands of walkers in the lake district every year. Its close to a famous pub, The Old Dungeon Ghyll in the Great Langdale Valley.