smurf

You presumably have a Campervanco conversion. As you have correctly pointed out, the battery on the seat is the 12V battery to power engine related 12V systems. The battery in the centre console is your leisure battery. There is some information on the battery, and where to get one from, in this thread.

Off the top of my head, I don't know. It goes right from the back all the way to level with the windscreen. It faces upwards. There is a photo in my linked post.

As you are in Stirling, if you are potentially looking to do a bit of preventative maintenance on the hybrid system then look up Hybrid Battery Repair of Glasgow. They can do the thermal paste replacement on the IGBTs, amongst other hybrid related work. I haven't used them personally, but they seem to get good reviews.

ATH10 does have a 4WD light, but it purpose is to indicate a fault, as you state. The hybrid display on the stereo head unit shows the rear motor in use, but there is nothing similar on the ATH20.

The rear motor is just a normal part of the hybrid drive. Every time you accelerate, the rear motor will be used to get as much hybrid assistance as possible. If it wasn't working you would be getting warning lights on the dash.

There are no left hand drive headlamps, but luckily the lights don't lift up on the left. They have a flat beam and only light straight ahead at the same height. How you would explain that to the Swiss authorities I, do not know.

1. Across the car running under the front seats. 2. The cooling fan is under the front passenger seat. 3. 12V battery is in the rear of the centre console.

Yes, they are under the air filter housing

I checked the manual the other day. It uses the camera and the head unit. There are no sensors anywhere for the lane assist.

It uses the cameras, but I think if you have removed the original stereo it won't work anymore.

From looking at the part catalogue, it appears to be hidden in the dash attached to the heater unit.

I haven't got any specific advice, but I have heard good things about using a vacuum pump to remove all the air from the coolant system first, and then coolant is admitted. With no air to get trapped there should be no need to bleed it. This is a kit I found on eBay, but I have no personal experience of using one LINK

I bought this one. Works well, is easy to put on and take off, and packs down small for storing. https://amzn.eu/d/0aowWRXb

Unless I've missed it, you haven't mentioned the Webasto heater. An expensive, and useful, add-on.

Google Duvalay. Probably does exactly what you want, but they are expensive.