Star Wars metal figures? any idea how much they are worth?

i have acquired a complete set of 9 star wars pre production new hope figures, created for the film including- jawa, R2D2, c3p0, obi wan, luke, han leia chewbacca and vader. c3p0 and chewbacca are gold, luke leia and han are silver and vader and obi wan are black and brown . originals from elstree film and tv studios 1976, the certificate is gold sealed and signed by N. Harrison. labelled the Danziger collection. i have been told by someone from elstree that they were made, but the maker didnt get the contract, and so then was asked to make them as gifts for film participants such as Harrison Ford. apparently there are around 20 of these sets. can anyone tell me anymore about these, and how much are they worth?