follow upto my ex won't return my house and car keys.?

Hi, thank you for all the answers I've had already. I have contacted him loads of times, by letter and text. He won't respond. He doesn't have the car, I do. so I can't say it's stolen.Everything is in my name, but I don't drive. I'm disabled and not well so at the moment I can't send a recorded delivery letter, or get a new door lock. (don't know how to fit either). And there are 2 keys to my front door, one is a chubb. So would be very expensive to replace. As for getting a new car fob, I thought the fob has to be configured to the car?? Why should I have to go to all this expense anyway. I'm angry because it is so simple! Just return my keys and take his stuff!!! There is no chance of us getting back together, so I think he is just being awkward and spite full. I think I will have to phone my local police for advice. I'm in the UK.