Well, Hugh, I thought that you were more interested in the tansalpine machines coming out of Milan and Turin! I know that you tend to ride frames in the 23"/57cms range, so maybe I should tempt you with one or two of my Helyetts -all earlier than the Ebay model - and all in your size...so that I might bid on the smaller model on Ebay!
I am trying to document Helyett bikes as best I can..and it is not an easy task ...and there appears to be no one out there with any information although I have been told of a chap in France who collects anything and everything to do with Helyett.
Curiously when I put a section on my Flickr site dealing with Helyetts, the Tourist Office from Sully-sur-Loire, where the later Helyett factory was basedm, emailed to ask if they could use some of my photos on their tourist web-site. So I now know better than to visit Sully - about 30 minutes from my house in France to try to get chapter and verse on Helyett.
You should be congratulated on your eagle eyes for spotting all those variations between the two recent Ebay Helyett Speciales ! I had not noticed that the pattern on the head-tube of the green bike was different from that on the blue one...the former being more like a Prugnat or early Oscar Egg. The seat-stay caps or indentations, with their deep flutes, on both these reecent machines are obviously a later design. Earalier models either had an ugly deep flute of flat plates.
What I find most interesting is the fork crown - a great improvement on the simple chevronned Wagner that Anquetil had to use. I have an early Helyett...before Anquetil's time...very interesting lugs and a two-plate crown, but not as nice as the one on these later frames.
The French ebay Helyett is my size and I have all the bits needed to put it back to original...so watch this space.
Norris Lockley
Settle UK