Thanks Bill
OK - I have the steel lens-surround ring off - it just slid off to reveal the plastic rotating lens assembly underneath.
Now comes the hard part. I'm not sure tha tthe insides are going to slip out at all. There is a built-up flange around the ball jointed mount area that seems to want to prevent the whole shebang from sliding off. This flange would need to be pushed or crushed in for it to be able to slip under the hole in the steel casing surrounding it. Did you have this issue?