@PUNKEY,
No, get down sounds more like a command.
We just tend to drop the 'at' or 'in', etc., in certain circumstances.
I suppose it should be down at the pub, or down to the pub, but we rarely say it that way.
"I'm going down the pub later, do you want to come?"
"He's down the pub and says he'll be back in an hour."
'Up' and 'round' are also acceptable, but it's much more common to hear 'down'. It depends on where the the person has gone, I suppose.
Down the shops.
Down the market.
Down the town.
Down the tip (nowadays called a recycling centre)
Round his Mum's house.
Round his mate's house.
Gone up London.
It's not proper and formal English, but it's how we talk in normal conversation. Other regions of Britain may differ slightly, but this is how we ordinary folk converse in and around London, and possibly the entire Southern half of England.
My favourite expression comes from Dorset. When someone is enquiring as to where someone has gone, he'll ask "wherezeeetoo then?".