Hello mate,
Apologise for not replying to your previous post, I didn't see it for some reason.
I did fit mine in the end, using the provided screws and sikaflex.
All pretty straight forward, although I did drill new holes (twitchy bum moment!) I find it strange/annoying that they don't use the existing mounting points on the roof rails, but obviously the brackets need to line up with the holes in the awning unit to secure it to the bracket, so it is what it is.
The sikaflex stuff creates such a good seal that I'm not really worried about leaks. At worst in a few years ill have to take it off and re-do the seal, but I can't see that happening for a good while.