Somehow the original chrome part became loose and eventually fell off. On inspection, it was a plastic part coasted in Chrome, so I thought I'd make a replacement in an alternate colour (to match the car exterior).
The original was simply a pull to remove and push to fit.
I printed this with a 0.4mm nozzle, 0.3mm layer height, and probably printed it a little too quickly hence the slight printing issue. No supports or rafts required.