repair rebound strap bolt
If it's pretty much flush you could try and drill it out using an undersize drill and retap the hole. If it's still poking out you might want to try and weld another bolt onto it and try and get it out that way, the heat should loosen the old bolt up a bit, but make sure the new bolt is welded on securely. I've had very bad experiences with bolt extractors so I'm very hesitant to recommend their use...
If you are a perfectionist, the lower strap pin is available for about $7.00 and must be ground off and new one re-welded. If enough meat is left such that the inside washer will hang on, clean the remaing threads and washer and put on with a tack weld. Otherwise, drill and tap using 1/4 inch bolt or stud with nut.
Search MG MGB Roadster Questions
MG MGB Roadster Experts