Good day all.
Been a while, but here is what I hope is the final update.
I took the car to the garage I bought it from in 2017.
This garage lost its sales franchise in 2022 (to the new place that spun the yarn about needing a 'franchised' battery), but is still an official Skoda service centre.
Re-counted the story / scenario - again, asked for a second opinion on the need for a 'franchised battery', i.e. the Halfords Exide battery was not good enough.
They plugged-in their diagnostics.
Battery 'coding' to car was fine in that they could not see any errors. Big-up to Halfords. 🙂
However, they found a stored fault 'neutral indicator sensor', that was responsible for the Start / Stop system not working, even with the needed Halfords fitted new battery.
This stored fault had not been picked-up in the two diagnostics performed by the currently franchised sales / service garage.🙄
Why not, I do not know?😒
Old garage investigated and found a broken wire from sensor, repaired it and now S/S system works.
Not sure exactly what to make of all the above.
It does raise conspiracy theories over the series of events if I had taken the new garages 'advice' and gotten them to fit their 'franchised' battery - when would the sensor error have been found, would they at any point acknowledge that the need for a 'franchised' battery was never the problem or needed, etc., etc., etc.
Oh, on a related point to old / new batteries I indirectly solved an issue that had been bugging me for about 18-24 months.
The auto door lock system had developed an annoying repeated, multi-clicking sound every every couple of minutes or so after initiating door locking.
Like it was testing itself, so I disabled it.
New battery, so for curiosity sake I re-enabled the system, no clicking, result.