I saw one of these today in a charity shop, it felt and looked to me to be modern and pressed glass (from a two part mould?). You can see the seam on the towbar in the last of the photographs above.
If anyone wants I will go back and buy it (assuming it is still there) and post it to them (all at cost). If interested reply by clicking on the mail icon by my name so as not to clutter this thread. Hope this is OK and does not break any board rules.
John.