I already had a rough design on the go and inspired by the photo from Brian I went to the garage and made one for myself.
This is what I did .... ( this is even more boring and tedious than the average Brockett post)
Four 17mm nuts, a number of washers some big and fat and the pegs. Pegs were made from stout tent pegs which were bent and bashed into a suitable almost eye type shape.
I put a dome end nut on the threaded rod and held it in a vice. Then added a washer or two and the first eyed peg, another stout washer and then nut number two which was tightened to hold the peg in place. Then I threaded a third nut onto the rod, added washers then the second eyed peg more washers and a fourth nut. In order to keep the pegs parallel I turned the fourth nut one turn and the third nut one turn. With the pegs engaged in the springs hooks I proceeded one turn at a time until the spring was stretched to the required length. The tricky part is transferring the spring to the bikes pegs which was done by making the spring a bit longer and easing the spring into place. This trapped thetool's pegs between the springs hooks and the bikes pegs but with a little shoving and pulling the tool's pegs came free leaving the springs in place.
The top picture shows the springs engaged on the bike's pegs with the tools pegs trapped between them.
