Thanks everyone - I'll check it out when I head up there in 2 weeks.

The only mention I could find (other than the Urswick school report!) was in the walk guide I mentioned - allegedly, "from early times to around 1810 it was the village custom to decorate the stone on Midsummer's Day in the hope that fruitful proceation would be stimulated" Sounds pretty interesting!

Cheers folks

Vx