Built-in Battery Charger

I've noticed recently that the battery is losing charge very gradually.  I doubt it is the battery itself a it is relatively new, so I guess one of my 'modifications' is causing a leak.   As it happens I have been thinking of buying a 'smart' battery charger (One of those you can leave permanently connected and it will not overcharge the battery) for some time, particularly as I am about to leave her for 3 weeks.   And we know now that disconnecting the battery is not a good idea as you lose the idle settings in the ECU.

But I also wanted one where I wouldn't have to keep taking the bonnet off to clip the leads on.  So I bought one that had a detachable lead and plug/socket.  It then has 3 optional types of lead to connect to the battery, a normal one with crocodile clips, one with a cigarette lighter plug and one with just 2 bare wires.  The first and third came with the pack, the cigarette one was extra.   So I used the ones with 2 bare leads.

So I wired the lead into the passenger footwell (The 6-way plastic connector on bottom right is connected directly to the battery, and you can see the red lead going vertically up to an in-line fuse).   This area is becoming even more of a 'rats-nest', I really ought to tidy it up.  On the positive side I know what every wire does

And the other end of the lead comes out just by the passengers arm rest.   This shows it with the charger plugged in.  In day-to-day driving it is nicely hidden away.   So now it is a 20 second job just to plug/unplug the car.

What's the odds on me driving out with it connected one day