Quick Release Clip or Hook...?

[Niall]

Yep bit of velcro strap, screw it to the plastic trim with self tappers then just wrap it around the handle. Or, bit messy but you could get a bit of threaded bar through the plastic which goes over the top of the handle and on the end, put a 2" length of metal sandwiched between two nuts so you can just turn it. Turn it down to hold the case in place.