I was having a clean around the engine bay on the van, and I decided to take the airbox off to get in the nooks and crannys. I thought I'd got all the hoses off, lifted the flysing saucer up, and there was a half inch rubber hose hanging down from the base (comes out inside the air filter element).

Any ideas where it's supposed to go to?

its likely to be the crankcase breather hose that goes to the back of the engine

Thanks fot the help. That certainly sounds like a likely candidate. Whereabouts on the back is it (centre/left/right)? Easy or a bit of a pain to spot?

I'm a bit of a stranger to this particular sort of polo engine, I keep catching the back of my hand on the fuel pump forgetting it's on the right

goes straight down to the back of the engine where it goes to the dome on the back of the block. there should be a hose coming off the pipe to the back of the rocker cover too

Thanks for that. I've got the little one, it's just this one that's been catching me out.