Hiya Chris,
that's a crackin' diagram. I would guestimate the sunrise as the point where the slope from Blencathra joins the flatter part of the diagram just North of Penrith. I would say that the first rays of the sun hit the stones at around 05:30.
I can't be more precise as I was a little distracted. I took my lad and his mate camping to Pooley for the weekend and dragged them out of bed at 04:00 after sleeping - in. I was worried we'd miss the sunrise so I drove like a nutter down the A66 with one eye on the sun rear view mirror. We hit the site at around 04:30 but we needn't have worried, the fells saved the sunrise for us.
We stayed until around 06:00. My lad was most disgruntled at having been dragged from his lovely warm sleeping bag and bundled into a field full of "strange people who scared him" to watch an event that happens every day, poor little bugger who can blame him? I'd brought a flask of hot chocolate, sarnies and bags of sweets but the little fellas were not open to bribery so we left as soon as the sun was up and everything had settled.