Possibilities for the gent from Perth.

Put some ND in front of the lens with a pivotted or hinged mount so you can swing it out of the way to focus. Or cobble together a slip on mount for same.

Use a speed losing developer - Caffenol / Folgernol etc to lose a few stops of speed. The "special" image quality might be an asset for reinactment photography.

Use a color negative film or the C41 BW and just massively overexpose. I have tried to everexpose color negatives so much that film was almost unprintable, and gave up since color negative film's latitude seems near boundless. The lab just seemed to be able to print from anything. I stopped trying to find the point of failure since it was cruelty to the lab to keep extending the experiment.

Can you push the aperture lever past the last marked stop? If so, test to see what stop it gives you. Might be useful to get you into workable speed territory.

By the way - greetings from New Hampshire! I've missed the "Wisdom of Uncle Dick".

C