if you know how long you have to leave the car for before it goes flat, then each fuse will take that time.

If your confident with an Ammeter then you need to chack the current drain, the only problem you may have is that if its a sticking relay then when you disconnect the electrics to fit the ameter link this may cause a relay to drop out anyway.

Do check those lamps above the sunvisor first as they were a very common cause of flat batteries.

2 nd haver you checked the battery itself incase the battery is faulty ! sometimes they do short curcuit internally.

Is the current battery a fast fit tyre centre one ? this is a very valid and important question as some of these batteries are fitted with post convertors that you wouldn't be aware of and they can cause havoc when the connection corrodes.

"Car would not start after 4 hours".So how did you get it started?

So, it turns out that there was a problem with the battery. Replaced it and everything was hunky dory from August 2017 until late April, when we returned from a trip while the Omega was left in the drive. Battery flat, recharged, and once again, would not start. Just got a click when turned on the ignition. AA visited, supercharged the battery, reset the electrics by locking and unlocking the car via the remote. Drove the car 20 miles. 2 days later, same thing happened,

Garage says put the car on a smart meter (permanently?). Left it on overnight with the result that meter showed 14.4v. Removed the smart meter for 2 hours, as I needed the extension cable. Put the meter back on again. Showd 12.4v. Not sure whether that's enough to start a V6.

Maximum exasperation

Any further help appreciated.

Here is the detailed procedure for carrying out the tests for key-on drain or parasitic current drain. Yes it's a USA video - but it's very well explained.

www.youtube.com/watch?v=zdIKNnwEjIs&ab_channel...s