[tc4332]

Did it.
It works quietly.
SWMBO is a happy bunny.

BUT, again mine is different.
Once indoors, unit on the table and I found a piece of string fitted to it. Nobody has mentioned this so I have taken two photos.

First photo is a side view showing where one end of the string is fastened.

Second photo shows the "hook" on the motor that the other end of the string is hooked to. I have written hooked because it is obviously designed to come off the motor whilst the other end is permanently attached.

Now, conundrum, what is it for, why has nobody else spoken about it.
My supposition, and I am open to other explanations from the more knowledgeable folk on the forum, is that it is to hold the screen mounting frame in the "open" position whilst working on the unit. Well it did that perfectly for me. The loop that was on the motor was the exact length needed to do that job.

I have also realised why the video emphasises having the vents open whilst pulling them out of the dash. It is because the centre vents have two flaps that are closed/opened by an arm inside the dash. If the vents are not open when the vents are pulled out there is a chance you could break the mechanism. Likewise when pushing the vents back into the dash. Note that these flaps are connected on the vent body by a plastic link which was missing on one of mine. Then another magic moment, the other link was an exact double of a piece of plastic that I found soon after buying the car. Nobody on the forum could explain what it was but being a bit of a hoarder I put the said plastic thingy safe. This morning I went to the safe place and there it was. Tried it and now my vents open/close correctly. Note that this only applies to the inboard vents, the outer ones are purely mechanical.
It took a long time. I started at 06:00 and finished at 12:30. OK I stopped for breakfast when management came to see what I was up to. She had heared me drive the bus in but finally realised I had not returned to bed. (I might have slipped up there, but then again the 8 is rather important). I did have another 5 or twenty breaks for cuppas and tv watching and chats with passing neighbours.
Now she needs a bloodie good wash and brush up, the 8 is a bit dirty as well.