No answer to my email but I have been checking him constantly - there is nothing in his fur (there was mention of ticks) and I have been using a nit come and checking visually. There has been no reassurance around his nose. Both his and Susans noses are clean and good.
Input and output is fine, so I have left it. Do you think I should chase her up on this Omi?
As it's something which has come and now gone and as he is perfectly fine in himself with no other symptoms, then I would not be concerned about what it was. I would, however, be interested to have known what the vet thought it was. I also think that your vet should have responded. So, if it were me, I would chase her up, but definitely not because I was worried.