Disco 2 Flat battery

My D2 V8 seems to flatten its battery if I don't drive it evey day. What's the easiest way to trace an electrical fault?

I was thinking about putting a meter on the battery and taking out the fuses one by one. Would that work?

It depends on exactly how you intend "putting a meter on the battery and taking out the fuses one by one".
A voltmeter across the battery is absolutely no use in this case.
You'll need to use an ammeter in series with the battery for measuring current. You should then be able to see the leakage.
There's always the possibility that your battery is on its way out or even given up the ghost.

I think I found the problem. The electric pump for the air suspension was working all the time, even though the ignition was not on. I heard it first and took the cover off to check, the motor was quite warm and vibrated slightly. After unplugging it, the noise stopped, I've now removed it and the pipework cos I converted the car to coils.

Our D2 with a 100AH battery sat for nearly 6 weeks when I had my heart surgery last year, started OK, so there isn't that much coming out of the battery.

Peter