Scannerdanner youtube channel is very informative too. Goes deep into diagnosing and always against the parts cannon.
Thanks, Jurassic. Not heard of him, will take a look.

Scannerdanner youtube channel is very informative too. Goes deep into diagnosing and always against the parts cannon.

Once you get the time, consider disconnecting the alternator to see if that makes a difference.
John
I think he needs to put his meter in parallel with the battery positive and the disconnected positive lead to really see what’s what, then maybe remove each fuse in turn.
I’ve reasonable knowledge in this field but not so proud to not employ a vehicle sparky!

Would the alternator take 0.3A for the first minute after connecting the battery, and then stop taking that amount of current, and then take it again later?Once you get the time, consider disconnecting the alternator to see if that makes a difference.
John

Our Landrover alarm would occasionally go off at irregular intervals. Once, it happened in the middle of the night and when I looked back on the cctv, because it was dark, I noticed that the interior light came on for no reason at all which set the alarm off. I just removed the bulb.Maybe the interior lamps (timer driven probably) would benefit too from bulb removal.
Would the alternator take 0.3A for the first minute after connecting the battery, and then stop taking that amount of current, and then take it again later?
For those reasons, I don't think it can be the alternator.
I have been measuring the current from the negative battery post, as shown in the video in my first post. That's how I found that one of the current draws was caused by the boot light.
Today I am going to spray WD40 on the boot catch, and see if that prevents the 'boot open' dash light from coming on, when the boot is closed. I wonder if, despite there now being no bulb in the boot light, the 'boot open' fault might be causing some other circuit to take power.
I have been measuring the current from the negative battery post, as shown in the video in my first post. That's how I found that one of the current draws was caused by the boot light.
Today I am going to spray WD40 on the boot catch, and see if that prevents the 'boot open' dash light from coming on, when the boot is closed. I wonder if, despite there now being no bulb in the boot light, the 'boot open' fault might be causing some other circuit to take power.
With reference to my alternator comment, any part that involves diodes can cause issues like this, but of course I can't say if this is on the right track at all.

As I've said several times now... by putting the multimeter across the negative battery terminal, and the negative battery terminal clamp - as shown in the video I posted in the original post!Not usually, but where are you measuring the 300mA?