HMV Gramophone spring problem

[Pumpkin]

I have recently acquired an HMV tabletop gramophone, not certain of the exact model number but it has the internal horn, lid and single spring motor.

The first test play resulted in lack of speed and what felt like the spring slipping when wound further, hence the motor strip.

The motor had plenty of black grease, not hard at all, just lots of it and came apart easily the spring was carefully pulled out from the center and “caught” in a bucket to reveal a small chip out of the end eyelet (pic)

The rivet on the drum is there but hardly projects inwards to permit any catching /engaging of the spring. The drum around the rivet appears to been domed out and I have tried to correct this by “punching in “ the metal with minor success, the rivet does not project into the drum far enough for the spring to latch on to.

For ease I have been using a bit of hacksaw blade to see if the rivet slot is accessible but no joy yet.

I would rather use the spring as it is even with the enlarged keyhole but I am not sure the rivet can be persuaded in further to accept the spring – and keep it. I am tempted to drill a hole in the opposite side of the drum, grind down the flat of a suitable bolt and affix the spring this way.

Is this a durable solution? Your thoughts and advice please and of course I lost the ball bearing in the strip down, what size should I replace it with? And where to pinch one from? Cycle head set comes to mind.