So I thought this was a classic British combo like tea and crumpets or curry and a cobra. It's been my favourite since I was a child. But I've moved to a big city and almost everyone I meet here looks at me really weird when I mention it.
Edit: just to add, I really think marmite is just mostly a flavoured salt spread which for pb like Meridian which had no additives and is basically like wet cardboard, its what makes the pb actually taste good.
Also just to throw this into the mix. Marmite and cheese works incredibly, maybe some ham and cheese too.