I think they were made by the same two German companies Weissman or Germar who also made hardtops for the W124 cabriolets. Unfortunately neither company are still in business -at least under that name??- sometimes examples come up on German ebay.de--- well made but they are not cheap! you are talking £thousands
Scrolling down the advert yields this:-
Morgana Management, Trading as mercland.co.uk. We are specialists in dismantling and recycling of most late model Mercedes Benz and Land Rovers. We have thousands of parts cleaned and shelved.We also have a stock of New Genuine Mercedes parts avalible.We specialise in Mail Order, Next Day Delivery.