That looks very similar to the Ocean 650 with Mariner Optimax that has been up for sale at Bembridge OUtboards for quite a while. I looked at it a couple of months ago, but the tubes were really worn and it needed a lot of work.
I noticed that they'd put it on eBay recently:
Ocean 6.5 RIB 150 Mariner Optimax | eBay
and it's still for sale??! Maybe it's a different one?
I wonder if someone was taking it for a test drive...