I am hoping Fluffy is home now, if not I have some suggestions.
I have been helping to reunite cats and people separated due to Hurricane Katrina here in the States for the last 18 months. Yes, we are still making reunions.
1. Make fliers and post them everywhere out to at least 1.5 kilometers from your new and old homes. Preferably with photos. There are some online places that have premade fliers that you can just plug in your own information then print it. Please make sure to note you want any information on possible matches including any deceased cats that may match his decription.
2. knock on all your neighbors doors and let them know your cat got out and is missing. ask them to please call and notify you if they seen any cat that may look like yours. Also ask if you can search their yards, under sheds any place he may be hiding. If they are not home, leave a note or flier with your contact information
3. call all the local vets and shelters. Give them a flier. Check the local sheters frequently.
4. See if you can borrow a humane trap from the shelter or animal control agency. This may be your best bet.
5. If Fluffy is used to sleeping with you, put something that smells like YOU outside for him along with food.
6. If he is afraid of outside he very well may hide, you need to be patient but persistent. One of my feral baby's got out 1 day after I moved. He knocked out a screen. I did not see or hear him for 14 days. I was up walking all night, shaking a food dish. Then one afternoon I saw him in the neighboring pasture. I called, he looked then RAN! I followed him and got him cornered under a neighborhing home. I sat there for 6 hours until I finally got him to come to me. He was SO happy once in my arms. I had to carry him around for two weeks then.
7. We have successfully used "game cameras" these are infra red motion detection digital camera $100 US. Set it up in your back yard to take photos at night so you can see what cats are showing up. Your Fluffy is the new cat to the territory so the other established cat may very well have pushed him off and are not allowing him to come back. So he may be a few doors down in a yard or garden that is not a territory to another established cat.
The most important thing when a cat is lost is to be PRO Active. Most people sit back and wait and that is the WRONG thing to do.
Please visit this site and look through all the links and stories. http://www.catsinthebag.org/
It will give a good idea what you are up against if you want to get Fluffy located again.
Oh.....and keep checking back at the old house. One of the rescued hurricane kittys was taken 50 miles away from home to the emergency shelter. He escaped his cage. 10 months later he showed up on the steps of his gaurdians Fema trailer, meowing his head off to be let in.
Cats are truly amazing creatures. Instinct quickly kicks back in and they will do what they need to keep themselves safe.
Please keep us posted on your quest and don't give up.