The butyl tape was perfect and seems to be very similar if not the same as what was on there before. When I opened the box for the tape, it said put it in the fridge for a few hours first to make it easier to handle. It had been sat in my garage for a few days which isn't much warmer than my fridge! The remnants of the old stuff were quite easy to remove and it was really easy to apply the tape - just a few minutes to lay it between the dotted guides. There was nothing messy or staining about it, so I don't know if
@Green51 was working with something a bit different, or if keeping it cold keeps it cleaner? The width of the tape was all over the place - it was meant to be 8mm, but it varied from about 4mm to 12mm, although that really doesn't matter in this application.