Thumbs up for this thread. Old but still hugely relevant.
Mine was still covered by the old seam sealer but it was flaky and not doing its job judging by the ongoing wet p/s carpet. Had to scrape the remnants off to reveal Botang. Picture here showing the relative straight line through the lower of the two holes. Plastic rivet as per MJ and have covered with SikaFlex.
Fingers crossed for dry carpets.
