"Borderer" vertical twin marine engine with reversing gear

A vertical twin engine to John Bertinat's "Borderer" design, described in "Model Engineer". Complete with Stephenson's reversing gear and water pump, it runs in one direction, not at all in t'other, so is going to need an eccentric repositioning - quite stiff to turn over, I suspect it has never been run for any extended period from new.

Height 5 inches
Length 6 1/4 inches