Thanks for the advice - keep it coming. I had the vet to the one set of trips we had last year - first born fine; second not coming. I couldn't feel anything I recognised and, with a third lamb behind it, I didn't want to guddle about. Turned out it was the shoulder! Anyway, vet got it out and the third one and they were fine.
We've used the same scanner - this is our seventh year with her and she's never been wrong
Here's a question. One single; a gimmer. Do I put her away with the hoggs and the two retirees with just hay or leave her with the twins, who'll be getting fed? My feeling is the former and hopefully, they'll all be too pregnant to notice her coming back into the flock for lambing.