One swallow does not a summer make.......but this particular road, featured
thus on 'Britain's Best Driving Roads' on http://www.speedlimit.org.uk/

...."Then there's the A817's sister road - the equally over-engineered but
unclassified route (it's an MoD road open to the public) from Garelochhead
to the naval depot at Coulport. This road probably has the most ignored 40
mph limit in the country (there isn't a building or junction anywhere along
its entire length), but the MoD police are so dim and lazy 60+ mph isn't a
problem...."

- is now subject to the national speed limit.

Amazing, and credit where credit is due, ie the Ministry of Defence.

S R