Dave:
Still loving your bike.........!!
Err, back to the post. Why not use your internal audit to measure this? You could use another 'process' and get into all kinds of extra work, but you already have a method in place - audits. Don't forget, they are part of the measurement section of the standard and if you choose to define the scope and criteria as the awareness etc., then go and select a number of people (some reasonable population, some newer recruits, if you have them, new in job etc.) and then ask them those things, almost right out of the standard.
Alex's questionnaire is fine, you might use some of that type of question, but I still recommend just auditing it.......
Andy