180K Sports Coupe rear cycle carrier

[teuchter]

Hi, I have just purchased a three cycle carrier, on fitting I noticed out of the six restraining straps the top two that clip onto the of the hatch/roof which is glass, is this strong enough, anyone else use one?
tia.

 

[ROBB]

I Have a C estate with a glass rear door as the 180K; It is not strong enough for a rear mounted carrier.