Fans on randomly - engine off and not started for 2 weeks

[FlipFlopGriff]

Mrs FFG walks by the Griff and the fans are running at full speed. Car is on the drive and not been started recently so why are they on? Given shes just had a knee op and struggles walking disconnecting the battery wasn't an option so got her to disconnect the connections at the top of the rad which did stop them. Anyone know where I can start to look to see where the problem is?
FFG

[FlipFlopGriff]

Thanks Barry. Strangely was happening on the pre cat earlier in the year and changed the otter. Is OK now but haven't driven it since. What are the chances of 2 going (this time the 500) at the same time?
Where does the wiring go when it disappears behind the rad, ie any more connections other than the 2 I can easily see/get to?
FFG

[FlipFlopGriff]

Ignition wasn't on, in fact the car was locked. It was only when a neighbour walked passed the Griff did she notice a loud noise.
From memory the fans don't run when the key is out?
FFG

[FlipFlopGriff]

Connected it back up after a few days and its been fine since.
FFG