OK, Noreen, I was miles out in that other thread. But from what Mbo says, even Groves is a bit off-beam on this one. I'm now 99 per cent sure you're right, thanks to your patience and Jon's blue clicky (I'd been to that site many times Jon, but always skipping the wordy bits). But even there. it's no quite black and white.

Thanks for dragging me back to this little matter Sheila. It's been bugging me for a while, but I never got round to making the effort to go into it in proper detail.