We have a batch of Impact Naomi saddles in white which are factory seconds. When they were built in the factory they had the incorrect bolts fitted.
This means you can't bolt most seatposts to them. If you are a bit handy and can remove a cover off a saddle, then swap the bolts for the new ones supplied you are getting a Naomi for £12!
Alternatively you could just run the saddle with the cover "tucked" down each side if you don't want to strip a saddle down.