Hi Claire , Welcome to JustAnswer. I'm a licensed veterinarian and I'll be happy to help. Your little girl had a medical problem and also a stressful change for her (your going away), so it's no wonder that she began soiling indoors! Now we have to get this turned around!
First of all, it is important to determine if she has a urinary tract problem and/or intestinal parasites. Secondary to the fleas, it is likely that she does have tapeworms unless your vet also gave her medication for this. If by "messing on the floor" you mean urinating, then I would also have a urinalysis done by your vet.
Once all is determined to be fine with her urinary tract and her bowels, then we can concentrate on her litter and litter box. Also, you have been very thorough in using a cleaning agent that not only removes the stain, but the odor too, so that not even your kitty can smell where she went. The litter you are using should be the same one that you have always used, and her litter boxes should be the same that you always used. I say boxES, because it is strongly recommended that you have one more box in your household than you do cats.
Next, cats will not go to the bathroom where they eat, so I recommend that you put food dishes down wherever she has pottied
You could also use a substance called "Cat Attrack" sprinkled in her litter box. There is also a pheromone spray called Feliway which can be calming to many kitties, and yours may still be upset by the episode with the fleas as well as your being away. . .cats take quite awhile to get over things! This Feliway also comes in a diffuser (a plug in), so that might be handier.
I did look up Jeyes Fluid online and it does say that it neutralizes pet odors, but I can't find if it contains enzymes. The best products we have here for cleaning and neutralizing spots and odors are enzymatic cleaners. One that I like is call Nature's Recipe. You do have to be liberal with the amount of fluid to neutralize it enough.
I hope these suggestions will be helpful. Again, I want to emphasize that if she is urinating outside of her box, then making sure she doesn't have a urinary tract problem by having your vet do a urinalysis is the first step. Also, having her treated for tapeworms if your vet didn't do this already.
I look forward to your response when you are able to be online again. . .
Dear Dr. Barbara, Velvet (the cat) is still urinating in her tray and my daughter gave her a worming tablet as I told her to do that while I was away. I left her last summer and she was fine when I got back and showed no signs of missing me. I don't think that my daughter was as fussy about cleaning her tray as I am. Someone told me to change her litter, but I use a good one and don't want to change it. I shall take your advice on board and let you know how things go. Thank you for your help. Regards ***** *****
Dear Claire, Thanks so much for your response. If I'm understanding correctly, Velvet is currently urinating in her litter just fine, it's just the stool that is outside of the litter. At least stool isn't so difficult to clean up!
The tapeworms that come from fleas are not eradicated by general dewormers, so Velvet may not have received the correct deworming medication. Do you know which dewormer your daughter used?
Hi, sorry I took so long to get back to you but I have mislaid Velvet's worm tablets. Can you recommend a suitable worming tablet for her please.
Sure. Praziquantal (Droncit = the brand name here). This may be available over the counter in the UK, but it isn't here. The dose for your kitty would be on the package and is based on weight.
I just noticed you referred to your kitty as a queen. Does this mean she isn't spayed? Hormonal fluctuations could be part (or all) of the cause of her house soiling issue. Queens go in and out of heat the whole spring and summer unless they are pregnant.