My FF had the spoiler on when I bought it but it is starting to irritate me, the ends are flapping about in the wind and tapping on the corner of the roof at each side.

Is there supposed to be any outer fixings or support?

I've got a feeling it may not be a genuine spoiler but I can't find them on ebay surprisingly, mine has the recess for the badge (with badge) the ebay ones don't appear to have it Current
2017 Range Rover Sport SVR
2001 Porsche 911 Turbo
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2013 Range Rover Autobiography SDV8
2007 Range Rover Vogue SE TDV8
2002 Range Rover HSE TD6
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Aero 1 had Badge imprint

Aero 2 had none...

neither should hit the bodywork and your right, there are many cheaply made fakes around That said, there should be two rubber grommets/stays on the underside to stop it vibrating when you close the boot... Are yours missing?

Must be missing as there isn't anything there, can't say as I've noticed a hole either for a grommet to attach to. Are the grommets anything special? from what I've read about overfinch the chances of buying some from them are slim to non. Current
2017 Range Rover Sport SVR
2001 Porsche 911 Turbo
_____________________________________
Previous
2013 Range Rover Autobiography SDV8
2007 Range Rover Vogue SE TDV8
2002 Range Rover HSE TD6
+ Many other non LR products

No, B&Q specials

OT a little, but is there any indication that the spoiler reduces the grime and dust accumulation on the upper and lower tail-gates? My vehicle gets covered in dirt in my dusty conditions so I've been on the look-out for a spoiler that directs air downwards.

PowerfulUK were going to redesign an earlier prototype to include forcing some air down but recently abandoned that design in favour of a L405 type of spoiler which doesn't reduce dust anyway.

Not sure if it's the spoiler, but the back end of my L405 gets considerably dirtier than my L322 ever did.

From bad to worse - that's progress!