Hi Brian,
sounds like you had a Rab C Nesbit moment in the supermarket. :wink: Next time you're there keep your eyes open for the gizmo in the pic, similar to one already posted but these are one piece, flexible although the grippy bits are fim and most importantly, very cheap.
Largest aperture is around 60mm and smallest 35mm but flexible enough to handle various shapes which is useful. I don't know what the small holes are for.
It was one of the big shops probably Tesco or ASDA where I spotted them and bought 2 for £1 each, wife promptly pinched one for the kitchen and although my hands are still strong it's surprising how often I use the workshop one.
Bob