Maybe he got waylaid thinking of where to put his tax disc? Life was simpler then in the old Form days.
If you now someone with a lathe simply cut off the thread of your existing bolt and drill/tap the remaining head. This then gives you the option of purchasing a cheap high tensile bolt 12.9 or higher for a few pence. Cut the head off the bolt to leave a stud and screw into tapped hole. Drill a hole perpendicular to new bolt through the new stud and pin. I normally drill and tap the hole for 4 or 5 mm and use a 5mm cap screw to pin. Once screwed in simply cut and dress flush with the round outer. Works well and avoids the need to rely on locktite. Obviously works as suggested as one piece but requires more time machining especially the hex head etc and why not use what’s already there.
