What a lucky spot Steve
Kris had a similar find a year or so ago, getting an early 70'd bendix by spotting the corner whilst looking at a cooker.
It was staying at a holiday cottage with one of these in the laundry that may have directed mum to look at and get the 18340 a year or so later.
Once again just as we may think, we'll not see one of whatever still about these classic machines still turn up.
All the best with the restoration, you'll do a great job as usual
Mathew