[Thermobaric]

Anyone had to remove a number plate screw insert and can advise the best way to do it?

My screws were a bit rusty so I thought I would swap them out. Of course one snapped off...I was able to get a good grip on what was left with some vice grips and of course that snapped off too when I twisted. How on Earth a small screw has embedded itself in a way that a steel screw snaps when turned rather than just unthread, I don't know. And yes, I've tried soaking in penetrating oil.

It's really awkward as it has two shoulders that compress when it's inserted and flare out when through. Looking at it now, I'm thinking maybe tightening a small cable tie to compress the shoulders?

Any ideas?