Wheel is in, honking ability present in full.
It turns out that all inner steering column shafts receive a coating from Porsche during construction.
When the upper bearing is pressed onto the shaft its the luck of the draw as to whether enough of this anti-corrosion coating is removed during said process to allow electrical continuity between the inner shaft, bearing and outer part of the column.
In this picture you see my rack with the central shaft removed, and the contact point now lightly sanded to remove factory coating where it meets the inner race of the top bearing, that is located in the outer part of the column. Once re installed Precision found/achieved around 4ohms resistance between the inner and outer part of the column. ( via the top bearing) . The bearing in the lower part of the column is isolated via a large rubber buffer, so no continuity would ever be achieved through that point.
Luck of the draw on how much resistance a rack provides when being built from new. Very little continuity is needed to operate the horn.
In addition to this non PSM cars need an earth wire run to the external part of the column.
My car now has a later, two-piece column in place that clearly was luckier than my original one during the construction process in terms of the coating being disturbed when the bearing was installed.
Precision are chasing down an annoying noise coming from the passenger air-bag area, which they believe will be resolved tomorrow and I'll pick the car up by the end of the week.
(I feel a little like the protagonist in one of those fables where you are on the bank of a river with a chicken, a lettuce and a fox, and have to get to the other side of the river with all three intact, in terms of shuffling the Jaguar, the Porsche and the Volvo over Christmas).
Anyway - probably the least enjoyable experience with the car, and one of the more expensive, but hopefully soon forgotten when I'm driving it again.