Thanks folks, I bought the Wiggle one.
A couple of clicks of the mouse, and I was able to lean back with a contented sigh. There is really nothing so satisfying as buying new tools. I understand some people actually go on to use them, but I may just keep it in the garage with the hedge trimmer, the garden cultivator, the Dremel look-alike kit, and the chain cleaning device, all still sparkling new. But you never know when they will come in useful.
Bryn