Some dunderhead must have seen the pic of the then GSRPS Ruston at Fenit, put 2 and 2 together and came up with 6 and three quarters. And as a final insult it's gone full James The Red Engine.
Some of the information boards and public installations of railway related things in this country are comedy gold, wild assumptions from local "historians", things copied and pasted from Google. Fire any old rubbish together and it'll do!
There's a cast plaque, which wasn't cheap to produce, at Manorhamilton station riddled from end to end with spelling errors. It has to be seen to be believed.