The water gauge cover looks definitely like early Doll.
The engine has a Plankish touch, but I think it may well be Doll.
I don't get your issue with the eccentric - could you highlight the cutout? The one I see is the usual cutout for the reversing pin of a slip eccentric?!?! But perhaps I have missed something...
Sorry, I 've only now found the other thread. It's good that sb else also sees the Plank genes... The eccentric definitely looks strange...