Technical Sporting Central Locking

[FPS]

Hi Everyone
I've got a 95N Sporting (running strong at 86K) and the Infra Red Central Locking system has become problematic. To start with it was just an intermittant fault but now it doesnt work at all. I replaced the batteries in the key fob but still no joy. There seems to be a reset button by the infra red detector in the car but I'm not sure if this is relevant to my problem. No mention of this in either Haynes or the owners manual.
Any help would be appreciated. Thanks.

 

[kebab]

changing the battrys is about all you can do on a car this old without spending hundreds.
the button is used for coding in new remotes.