Battery dying & high parasitic drain

[Lazman]

The battery in my 2012 Insignia 2.0 CDTi keeps going flat.

It was only during winter that would happen at first, I had to go out & start/run my car for about 30 minutes every other day to keep the battery charged (when I wasn't using it everyday due to working from home).

Now it's doing it no matter what the weather is like.

I've checked the parasitic drain on the battery & it seems very high (at 3 - 5 amps) with the ignition off & the key in my pocket.

There were three piggyback fuses for some things (one of them I had fitted for a dashcam, two seemed to be dealer installations), I disconnected all the piggybacks & checked the drain again - no change.

Any ideas please?