Heath Robinson would be proud

I told you it was a bit of a cobble but as you can see, it does seem to work.
Attaching the lens is simple, the spring loading on the adapter is spot on and it centers every time, not at any time has it looked like coming  detached.

At full zoom it gives a working distance of about 10 inches,  which is  really  handy, as it allows enough room for the flash not to cast a shadow and makes for good working room.

As you can see I am very happy with this inexpensive piece of kit.