My problem concerns our home security lighting system.

We have two floodlights,

two PIR's and an internal control panel.

The control panel inside says GJD Sapphire MkIII.

After several years of faultless use it has now gone wrong.

Sometimes the lights only flash,

sometimes they are ok.

I think it is either one of the two PIR's giving a faulty signal (with the other still ok hence it sometimes works) or the timer in the control panel.

I tried altering the time on this and they seem to stay on longer when they do work,

but usually they only flash.

Should I change one of the PIR's or what.

I really would like to talk to a real person!

It sounds to me that the internal switcher is faulty, it needs to be replaced. However I would start by disconnecting one of the sensors and monitor the system. If this makes no difference reconnect this sensor and disconnect the other one. If this makes no difference it is definitely the switcher.