The best solution we can come up with (and backed up by a few people who should know) points to the remains of the chemicals used for stripping the paint as the main cause for the problems. But why did it take almost two years for the discolouration to show? This is almost certainly down to the fact that the car was out in the rain for a prolonged period waiting for recovery in Austria after the break down on the Timmelsjoch during the 10CR. This triggered the remaining chemicals to react with the water based paint causing the discolouration. The car was actually soaking wet inside and outside when it was returned from Austria.
In the meantime I have been able to work on the car on and off and hopefully it will be fully re-assembled within the next few weeks. Leaving only the gearbox to be replaced by the one I am still rebuilding. Well actually I haven’t done much to it over the past weeks because I have been waiting for shims for almost two months now. Luckily S&S preparations managed to sent some over which where to thick but I was able to have them machined down a bit. But as the gearbox is at home and my tools are in the shed, finishing the gearbox will have to wait a few more days.