Quote:
looks like the shiny one has been plated (after leaving the mint)

The weight difference of 0.04g could maybe be due to the sensitivity of your scales ... have you tried weighing a normal 2 pence on the same scales for a comparison?
Also the newspaper article that you linked appears to more for interest rather then fact ... I'm pretty sure that if it really was a genuine error coin then they wouldn't have just auctioned it on
ebay!