Xmas do, at a Restaurant, small number of people...dress or trousers and top?

[ScientificProgressGoesBoink]

Help. Need a new outfit for works Xmas do, meeting new colleagues for the first time so want to look fab. Am 5'7 a size 12, (10 in some places as I've been low carbing, but not quite the body I want yet, so nothing too body con)

This is a department do rather than company wise so only going to be a dozen of us, and as I haven't met most of the department yet (just moved) then I have no idea where to pitch it. Please style gurus, help! :)

I'd go with a dress, simply because trews would probably be uncomfortable for a big meal and long sit.

We have a team night out and a whole office night out and I'm wearing a dress to the office one and trousers, top and nice shoes to the team one which is a meal and drinks. Hope that helps. Have a lovely time!