In reply to dave frost:
The address in the 2000 NDC guide was correct at the time. I know, because I went through the permission hoop myself when editing the book and took my dogs for a walk round the headland. Sadly, though, Il Duce was not within my repertoire (then, now, or ever)!
The current postal address is English Heritage, South West Office, 29 Queen Square, Bristol BS1 4ND. The grade remains at E5 6a in the new South West Climbs Vol 2, which has a nice picture of the route and is due out in about a month from now.
John