I'm sure I've seen little limestone outcrops (not big enought to boulder) from the M6 near Shap - is there stuff near there then?
There is also some bouldering at the Penrith end of saddleback, I forget the name off hand, take your brush though as it gets very little traffic..
Do you mean the Carrock Fell boulders? Just up past Mungrisdale on the roadside?