What he said ^ :)

I'll measure an M6 rivnut in a bit. 9mm is probably about right.

Good idea, but I don't have any, or the tools, but I worked out a slightly better bodge. ;)

Popped to the local DIY shop and acquired some M6*25 bolts and nuts (only need 1 bolt!).
Inserted a bolt up through the hole from below and attached a nut from above. Checked location, length, ability to fit trim and then tightened the nut really hard to make a captive bolt.

Another nut and then a big washer and one more nut and we had a "platform" suitable to support my existing trim (after a bit of levelling/tidying on the underside).
Finished off with reusing the grotty washer from the original bodge (happened to be the right size) and final nut. Not elegant but it holds and can fairly easily be undone.
Could do with a cover for that recess though......

And, as is often the case, having bought some parts I never used them, ended up reusing what I had, which also saved on transplanting all the heated washer jets, piping and wiring. ;)

I did remember, as advised earlier, to use copper grease on the wiper arm splines, though they came off fairly easily.

The final result is a tight fit all the way along the base of the windscreen, now including the central section shown here:

I'll stick a rivnut in there when it comes over in the spring then +++

It will need more than that if you do, the trim is missing the "pillar" that would allow a bolt to go through to the rivnut. So it will be a different bodge or replace the trim.
Luckily I have a spare one....... (though it has a bit of minor damage at one end that I need to sort out)

You wanna job fixing tractors HP's :p

Great stuff +++

Next time change wiper arms and wipers to genuine new.
Then only change rubbers every year. They are available to order via TPS.
They are made in Germany by company called SWF which is premium German brand +++

I've got the original arms for "show" but prefer the "aero" type for everyday use. They're also slightly longer giving better coverage (26"/24" vs 24"/23").

A further intriguing little twist on the body lugs below the windscreen and the slots they slip into on the plastic trim.
The bodywork on my S8 has two metal lugs, about 10cm outboard of the washer jet locations, this is the offside one.

http://forum.a8parts.co.uk/attachmen...7&d=1506521544

Both the trim on my car and the one I bought from our sponsors have the same part number 4D2 905 097. Yet the purchased one has THREE slots and it looks as if the fourth slot has been cut off, it has a manufacturing date of 12/94 and came with unheated washer jets in situ. The extra slots are equally inboard of the washer jets so I guess some cars may have had lugs there.

I felt along the bodywork and there was no indication that my car had ever had the inner pair of lugs, maybe it was a PF thing and they were later dispensed with as superfluous?
The slots are a plastic piece that is added on later, fitting over plastic projections and heat-welded in place, I think mine only ever had two..