hi mate. I ve had a leak problem about two mounths ago. Dealer told me that it was the profile gasket and the vacum pump O ring that had to be changed.
Due to the hard to locate and maintenance position and after a good TIS reading I ve seated to the axel and paied 240euros to the (st)dealer for half an hour work and three hours wait time for the glue.
Any way you ll need TIS and patience.