I've only seen UK Marmite a few times, and I would describe it as having a tar-like consistency, more viscous than honey, but would still 'pour' off a knife. Vegemite is more 'solid' (but still spreadable), like peanut butter or non-melted butter.

Probably depends on the temperature it's stored at. It's definitely runnier on warmer days.

There’s two types of UK Marmite, the standard thick spreadable version and the squeezable version.