Fashion Exclusive: the Flat Cap is back!
Simple physics dictates in order to view 'a 180° wide-angle view' you need the lens to protrude infront of the lens frame, in order to see both 90° up-down/Left-Right from the centre line. as such true 180 fish eye lens' are usually domed. Judging by the flat lens cap with this camera it is clear this is not 'a 180° wide-angle' Lens.
Perhaps Mr Paul Smith is making a back to his Nottinghamshire mining roots flat cap statement.