Update - been a crappy day.
Early this evening Inca started vomiting together with pure liquid diarrhoea. No bad smell, just sick, really sick.
Thankfully I was able to get hold of my vet on her home number. Following inspection of the vomit, my son and I found a small piece of red stuff. Looked like maybe a peg chewed. looked round the yard everywhere, then my husband remembered he had whipper snipped the fence lines on the weekend. He said he had a problem with the whipper snipper cord. Located the cord, and sure enough, it was red and matched the coated wire in Inca's vomit!
So, all water has been taken away from her (on strict instructions of vet) and she is having sips periodically of Yakult. Now the question is to ascertain tomorrow is there more in there, is there an obstruction, or is this just another bout of upset stomach?
Oh the joys of puppyhood. I'm exhausted from stressing I think. She does seem a bit more comfortable, I must say. Will see what tomorrow brings.