Originally Posted by
Aquila1
What's the source of that second Ordnance survey map? I ask because Black Rock is clearly shown on that map you have posted yet as per my last post, it or it's lighthouse doesn't appear at all on OSI mapping at 1:50,000 which seems to be very much an anomaly as far as I can see.
It's from
here
Both are clearly shown on the paper 1:500,000 and 1:250,000 flight charts, but the crew would probably not have been using these I'm sure.