Spent a couple of hours on the car this morning and everything went exactly according to plan.
The hardest part would have been removing the plastic covers from around the wipers, however, Mr Autoglass did that for me on Tuesday when he fitted the new screen.
So, this is how it went; stick some tape on the screen to show where the wipers are at park, then remove the wiper arms by popping the black caps off and using a 13mm socket. then remove the plastic scuttle. You need to be really carefull doing this as the plastic clips are very fragile. Mr Autoglass gave me new side bits as part of the screen install and I am pretty sure you are going to break these getting them off, so try not to disturb them. the two scuttles should come off without having to remove the side bits, after all, this is how the service department get to your pollen filter. this is also a really good opportunity to clear out all the leaves and sweet wrappers that have blown into the cavity beneath the trim.
I took the arms away, dressed the notch nice and flush with my Dremel and re painted both arms with some satin black.
With access to the wiper assembly, it's just a case of removing 2 M6 screws and a nut and the whole lot comes off in about 2 minutes. The photo shows the old fixings on the drivers side. I re-assembled it with lots of copper grease and a big washer in place of the little one. the washer must be M6 and must be bigger in diameter than the plastic housing. I did this in all 3 positions and cramped it down till the steel tube in the bush was well and truly squashed. I actually swapped the original nut for a nyloc and the hex head screws for cap heads with spring washers, but I'm just fussy.
Next, make sure the wiper assembly is at park by flicking the wipers on with no arms fitted. Re attach the passenger arm in it's original position using the tape as a guide. Re fit the drivers arm but make it a couple of splines clockwise so that it parks lower than before. NB. Do not attempt to move the wipers or mechanism with the key in the ignition. It gets really pi**ed off and makes very funny noises.
Put all the trim back and admire your work. The arm sits about 5mm lower in the body and the arm does not contact the bonnet. You can see the small difference in the full sweep position in my before and after pictures.
One other job worth doing, I have always noticed that the plastic scuttle on the drivers side holds water in the wiper spindle recess. to stop this I drilled a small hole in the plastic before I re fitted the trim. There is already a similar hole on the passenger side? (see picture).
Thats about it folks, easy to do, just cost me a couple of washers, paint and some grease.
Your Alfa dealer would never do this as it would be a modification and they don't do that. they would just sell you a new mechanism for £150 that you don't need.