Where do the different granite pebbles at Silloth come from?

 We found a selection of different granite pebbles at Silloth. The one on the left is definitely from Criffel.

This display board from Watchtree might give some clues. It shows ice sheet movements during the Ice Age. Southern Scotland looks the most likely source but Shap is also possible. Cr means where Criffel erratics have been found so would be the southern limit of that ice sheet - where it butted into the Lake District ice.

There is one other detail that I have mentioned before - longshore drift moves pebbles from north to south above St Bees head, but south to north below. This should mean that rocks from Ennerdale might make it to Silloth but not from Eskdale. I need samples of granite from lots of places to compare to the Silloth photographs.