Is it correct to say stood or standing in this sentence?

Posted by letitrollpanda@reddit | AskUK | View on Reddit | 2 comments

This has baffled me since I moved to England. I learnt to say "I was standing at the bar..", however i've noticed most English people say "I was stood at the bar..". Similarly, I would say"I was sitting with my mates..", whereas people i've met here say "I was sat with my mates.." It might be a local dialect for SW England, but it bothers me as it sounds wrong to me. What is grammatically correct?