Hi, well bought a small metal tin, with metal lid. Put my key in it, had it near the car with me, and it still unlocked with the keyless entry on the doors. So a metal tin does not work. I have since bought a pouch off ebay, it is called a Defender, item number
223245023668 Defender signal blocker, £4.79
I has a lined pouch, and put my key fob in it, then went to try unlock car at the door, had the pouch in my hand, and car would not open. So this pouch actually works. So now if I go out, will put my key fob in this pouch. Worth having a look on ebay.