Galaxy 2 series - remove zone no longer in use

i moved in to a house with a galaxy g2 wireless alarm system - I have all the codes.
One of the wireless PIR units kept giving a battery low error every month or so. Replaced the battery and everything was fine. After replacing 10 batteries I figured it was time to replace the unit, which I have done.

However, every time we set the alarm, it still shows lowbattery warning for the sensor that is no longer in the system (I threw it away)

Maybe I'm being stupid, but I cannot find a way to remove that zone (3) from the system.
I have set it to inactive, but still get the warning.

Any ideas?

Thanks
Twindy

 

Set to spare and delete the serial number from the zone.

 

Perfect, thanks very much.

 

Perfect, thanks very much.

 

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