Probably shouldn't say this but I USED to own a Cybervision 64/3D. It didn't have a scan doubler module. And I remember it looking rather similar to that. For it do be an IO extender it would have to be a dual serial with a missing port. I think it's more likely that it's a Cybervision.
Bet you wish you won it the first time. 50 quid! I know I do!
