I have the same roof rent and I have just replaced after the bonnet had flown up. I have made a mod to it as if its raining you do get wet even with the internal vents are shut. the holes that are in the roof put a rubber trim round to try and stop water running in.
car looks well we have just took delivery of a sadev st 75 14 the other week just to make sure I'll be able to keep up with you and your dad.
Putting a rubber ring round the holes is something we had thought of doing, plus i'm going to have a go at making some kind of bung for when it's raining and not needed. Not the easiest shape to make something for though.
You won't have any trouble beating me, i'm just going to be trundling round looking after the paintwork!