They're found in this set, one of my favourites:
http://collectobil.com/catalogue/items/3842.htm
That sure is a great set that I would love to get - the only bit I have got of it is the plastic screw that clamps the unit down to the edge of the table

I found that I was missing one of those gold hooks on my 3938 pirate island so it has gone straight into use.
Thanks everyone for your help
