mjt

Can you post a photo of the sensor?

I don't think it's an adjuster. I suspect it's something to do with crash resistance but hopefully someone more knowledgeable will be along soon.

AFAIK the Duratorq is a diesel. The petrol is a Duratec.

We have noticed!

That's an interesting-sounding procedure. What does it involve?

TBH the stop/start is more trouble than it's worth. Unless you are routinely held up in queues in an urban area it's really not worth worrying about and just think of the wear and tear it's saving on the starter motor and flywheel ring gear. When I bought our Mk3 in 2016 the stop/start worked sporadically for a few weeks then stopped. I didn't bother with it and ran the car until 2020 when the battery finally gave up. After I changed the it (it was a Ford one so quite possibly original and eight years old) the stop/start began working again and has been ever since. The point here is the stop/start stopped working when the battery was only four years old but the battery went on for another four years without any other problems.

Is it possible the windscreen seal has broken down?

Surely if that's the cause it's only going to be an issue if the lights are on while the engine is being started. The obvious work around is not to switch them on until the engine has been started (and turn off stop-start when running with the lights on).

Sounds like the common instrument cluster solder joint problem.

I've seen others on this forum recommend replacing with silicon rubber hose but I've no personal experience of this. I can only suggest doing a search on Ebay. Hopefully one of the more experienced members will be along soon with suggestions.

From those two observations I'd say it's almost certainly a split hose. When looking for a split in rubber hoses bear in mind that it will close up when the engine's not running so may be hard to spot. If you can, get someone to rev the engine whilst you look for it.

No, it should be Stop/Start it . . . . .

Now I understand the reason for your current avatar. And yes, getting old is no fun!

True, you could build up a really high temperature in the cabin but the hot air held so much moisture that the condensation would literally run down all the windows. At the time there was a kind of double-glazing plastic panel on the market that could be stuck inside the rear window to keep it clear. From what I remember it was surprisingly effective. Temperature control was by a valve that controlled the flow of water through the heater.

Reminds me of my first Mini. Those only had a recirculating heater. They used to be called "fug stirrers" On a really cold day with the heater on max it could just about clear a hand-sized patch above each vent.