I decided for £15 it was worth having a go, so I've put in an order. I've been playing with frets all my life, so I think I've got more chance of getting a smattering of fiddle-playing with this. And I note that the Fiddle Fretter "can easily be removed anytime and put back on anytime."

I'll report back in a few weeks when it's reached me and I've had a go with it.