Yes! This puzzle was virtually impossible to solve...the owner himself doesn't know much about it and if you saw that car at Padova last year (where I took this pic) you probably have seen the papers: in those pages there are just the emails I sent them long ago with the story of the car I've been able to re-built thanks to matramurena, who actually found out the background of it and was able to contact some of the builders too.
The story is not yet completely discovered and details are coming from time to time, but the car was built at the technical school in Zaandam and if you noticed some similarities with the Havas the reason is that Age Lammertsma, who was an automotive teacher on the Lower Technical School in Zaandam, was also the owner of the Havas at the same time this special was being built. They most likely took it as an example.