Guys,
The product I used was developed for flat face, gasket free sump/final drive installation and is extensively used in industry.
My covers had been sealed before I bought the car. it was clear that the previous hands had not wanted to spend the extra time cleaning of the old sealer. Also from 35 years working in an engine laboratory for a major car makers R&E department, I know you have to let this stuff cure. My guys loved it because it gave them a rest !
The bit that surprised me was the very small vent hole in the casing at either end where the link pipe goes on. I resisted the temptation to enlarge these vents to ensure lower case pressure.
By the end of September the car will have covered over 2000 mile in Europe with a good stint on the Autobahn. I have a tour booked, there will be no prisoners some will be pedal to the metal driving. Let's see what falls off 😎