Thanks for the advice.
Unfortunately, I think the only way to not receive retired pay is to not retire - until aged 55. Which further makes my AVC useless.
I have dug-out my 'Personal Financial Portfolio' that Sun Life Of Canada (SLOC) sent me when I started the plan. I have not signed it, neither has the sales supervisor. It tells me that I plan to retire when I'm 55. It also says that the plan has been recommended as a 'top-up' to my employer's scheme, as the maximum benefit from the AFPS is based on 16 years service.
Time to put my big boots on and wade in deep then... Will report back later, in case anyone's interested.
Again, thankyou.