Cats that recover from an initial bout of cat flu can go on to have the symptoms you describe, the red, watery eyes, snuffles etc. I had two cats with cat flu, one who had a very serious initial infection, although with antibiotics and home nursing she recovered - but went on to have flare-ups every now and then. The other didnt have such a serious initial infection, but also had occasional flare ups. Generally they used to have antibiotics and bisolvin, my vet also used to advise putting the cats in a steamy bathroom.