After a plethora of these on ebay recently its time to write a quick guide:
There are 2 types of plates/bowls that have GENUINE pixie graphics on them:
the MEGA RARE 1950's advertising plates (note not bowls!) of which there are only a handful in existence (GREEN SHIELD)
the CORNISHWARE COLLECTORS CLUBS plates/bowls which all bear the CLUB backstamp and look substantially different to the 1950's predecessors.
If you see a piece with a Pixie on it and a black or green shield it is almost certainly fake. A whole batch of these must have been knocked up a few years ago now and are still widely circulating unfortunately.
Quick way to tell the real item from fake on the Shield marked pieces: look at the Pixie's hat - if it is white filled it is definitely a fake. If it is filled in with blue it is more likely to be the real thing.
Lucy & Pete (aka Cornishware.biz)