Out of interest I had a check on the arrangement of the "Comfort Kit" while I was down in the lock-up this afternoon. The riser appears to be stainless so presumably a reasonably hard material and the bolt is a Grade 12.9 M14 which is a simple bolt, with no tapers to potentially prevent the riser seating fully down. The bolt is done up very tight taking a fair old swing to undo the nut with a long ratchet and socket. There is also the brace from the top of the riser to the upright though I don't know how that is actually fixed to the upright to prevent any movement at its connection.
Relying on an M10 (or indeed M12) Grade 8 seems like a large reduction in available strength compared to M14 Grade 12.
MMC Supplied Comfort Kit Bolt
