[kai]

You're welcome, Greg!

And I did leave it in the vinegar overnight and this morning it looked pretty good, so I washed it thoroughly in fresh water, dried it and have left it soaking under a good dose of WD40 while I’m at work today

Yup, that's fine for initially displacing the water; keep it soaked (wrapped in plastic) and get a good oil for longterm storage.

I did set the blade up so as to keep the ivory hilt clear of the vinegar while soaking it as I was very mindful of damaging or discolouring that and it seems quite OK.

Since vinegar evaporates, this is not a safe approach. It may be weak enough to not posit an immediate threat to already patinated surfaces though.

Rust developing on a tang will crack the base of the hilt sooner or later. Thus, I'd suggest to remove the hilt for cleaning purposes, anyway. If set with resin, it usually comes off reasonably well if heated long enough; if tight from rust, it may need many more heating cycles. Reattaching the hilt is usually done with a gentle pressure fit nowadays which allows the materials some inevitable movement due to temperature and humidty changes (the more these environmental variables can be stabilized, the better for longterm storage).

I will take some better photos this evening and will include a better profile of the hilt.

Thanks - pretty much all sides not yet shown (including the face) may exhibit some details that allow identification.

Regards,
Kai