Just for what its worth (or fwiw in Gen Y speak)

Here is my canopy lock.. Pretty simple.

Both locked and unlocked positions shown. The barrel has a 10mm diameter pin on the inside that engages with a hole in the dorsal fin. I have 2 holes.. one for fully closed and one slightly open for hot days.

The only issue is to make sure you have the keys before you lock it..

I like it!

Much simpler (ie. better!) than what I was planning - where did you get the lock GR?

While mooching around the a locksmith.. waiting for Vicki to pick up her mail from the post box.
Nothing hi tech.

Thought I could share with you my idea which was prompted by an unwillingness to drill holes anywhere. The left hand 'hook' fits around frame 4; the r/h hook fits around the forward steel bow of the canopy and the key ring provides purchase to pull the lock to the outside after which the security bolt is inserted. Projection is only about 40mm which is easily covered by a canopy cover, if used.
All the best.