There isn't much here about SB rotary mowers Rod, but there was a thread not long ago that attracted a fair amount of discussion:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=35770

Most likely you will hear from the contributors to that thread about your mower, which sounds like a 19" Model 47. A picture would be appreciated: I'm not sure we've seen a Model 47 so far.

Is your pen name based on the Plymouth Belvedere that was popular in Australia in about 1959? Sharp looking car at the time, I even remember it.

Last edited by grumpy; 27/04/12 05:15 PM. Reason: Add detail