Sorry can't help on this one. My Dad was actually in the wildlife film industry during the 60's and he did some work with Ozzie Bristow, so I would have hoped to have been able to help you, but I haven't come across Ron Shannin. Sadly my dad passed away a couple of years ago so i can't ask him. The Lion and Cheetah park outside Harare is still operational and Ozzie's son Viv, I think runs it now, they should know.