Maybe - I'd always thought oats were one of those things that just didn't go off, like tinned veg.

I don't have any maple syrup - I don't particularly like it, though I might try making it using a combination of golden syrup and sugar rather than vegan marg and sugar.

Leaving it to cool before I cut it wouldn't even have crossed my mind:-) It's always easier to cut stuff like flapjacks when they're hot - besides you've got to cut them so you get your first slice to eat!