Glad I found this question and people's thoughts - couldn't quite believe my eyes just now.
On holiday near Great Yarmouth and have just been looking out to sea (10pm) on a crystal clear night and can see lots of what can only be lightning strikes right across the horizon in the very far distance - quite a light show.
Checking a lightning strike radar, the nearest storm is north and south of Amsterdam about 130 miles away over the North sea - Wikipedia was suggesting that 100 miles was the upper limit but my experience (along with others on here) seems to suggest that it is significantly more than that.
Tried to get a picture/video, but only had my phone and it really didn't register, but impressive to the eye nevertheless.
