Focus remote not working

[Frik]

Ford-types!

The remote function on my Mk1 Focus has ceased functioning and changing the battery hasn't cured the problem. The key still operates the car fine, I just have to be a lot closer to unlock the doors - close enough to put the key in the lock and turn it.

Any ideas how to cure this short of being shafted by obtaining help from my friendly local dealer?

[camgear]

Does the fob rattle when you shake it?

[Frik]

Nope. Nothing loose as far as I can see.