Key fob not working AUII Wagon

[OffRoadFalcon]

G'day everyone,

I've been having an issue with my key fob and central locking lately.
So over the last few months it was taking longer and longer for the car to respond to the key fob, and eventually stopped working entirely. The light on the key fob didn't light up either. So I replaced the battery thinking this would fix it, but no!
The key fob works as normal, with the little red light flashing as soon as I press the buttons, but the car's central locking doesn't respond at all.

Any ideas?

Thanks,
Chris