About 5 years ago I fabricated a hidden towbar for my Edition 30 to carry my mountain bike.
I used a genuine witter towbar and the fabricated a detachable swan neck.
It works great and is fully hidden when removed. This is only suitable for the use of a single bike carrier and not to tow anything!!
So, I'm thinking of selling it now as I've got a VW Transporter. I was going to keep hold of it incase I get another Edition30 in the future..
If anyone is interested in buying it, let me know, not sure on a price yet and need to look for my photos of it fitted!