Hi Lorraine
My heart goes out to you, I am sorry that Cleo is still awol.
I know the pain believe me, my Gizmo disappeared four years ago, it was as if she just vanished off the face of the earth never to be seen again.
I suppose the worst of it is not knowing if she has been killed in an RTA but with the absence of any body that can never be determined. She could have jumped into a car/van and jumped out miles away and either be living somewhere else with somebody or living feral. Alternatively not all cats are very loyal and it could be possible that she has found herself another home. My working colleague had a Siamese cat that went missing and she found her cat two years later two streets away, she had simply chosen to go and live somewhere else, however I believe her cat went missing after a greyhound was introduced into the house, could it be that Cleo did not get on with one of your other cats.
I have a cat Spotty that came to me as a stray, he just walked through the cat flap (twelve years ago) and made my house his home.
I do urge you Lorraine for the sake of yourself and your family try to move on. I know that you will never forget Cleo and I don't blame you for doing a head count because I do that myself quite often.
I hope you are ok - thinking of you