It was quite shocking how quickly Merlin deteriorated - he had nasty diarrhea over night and this morning, and although he seemed bright and fine in himself I took him in to our vet at 09:00, since we'd had such a fright with Poppy two weeks ago. The vet and I both thought he would be ok without antibiotics, but by the afternoon he was suddenly pooing bloody liquid (sorry to be so graphic) and quite apathetic, so I called the vet and she came out and met me at 15:30 and gave him an antibiotic injection. (He is no better so far, and in fact has just sicked up his breakfast.) At around 6pm OH took Poppy into the woods and said she also has diarrhea with blood, so that's when I called the vet again and took her straight in. She says she'll see them again tomorrow at 11:00 if I think either of them aren't doing ok. I am feeling a bit shaky, and prepared for another difficult night!