A right pain of a person, usually awkward, rude, or just hard work to deal with. Said with a mix of disbelief and judgement, like you have already tried being polite and it got you nowhere. Can be mildly teasing, but it often means they are a nightmare. Honestly, it is classy shade in five words.
"The new manager’s a proper piece of work, banned lunch at desks and stuck a bell by the kettle. Now she pings it like we’re in primary school, absolute shambles"