I am indeed about to attempt replacing the insert with one sourced from the Bay - I found one that has the drilled dot as well - it looks exactly like the one on the watch, but we'll see, when it comes to fitting it. I'm still waiting for it to arrive.

I do the same thing as a matter of routine on my Seiko divers and as you say the insert is usually held in with some sort of adhesive - I've seen double sided tape, superglue (!) and some yellow brittle stuff. On a Seiko, it's really easy to pop the bezel, but my Heuer has much less of a gap between the base of the bezel and the watch case, which is why I posed the question.
I really need a new bezel as well - some dings and gouges are evident - but this will have to wait until one comes up, at the right price.

I wouldn't like to attempt removing the insert with the bezel still on the watch - too risky for my blood!

Ross