Hi Emma

That's an awful lot of people to organise an interactive event for. Could you give us an idea of the budget and what support you have?

Team building? Do they know each already?
The organisational restructure? Is this a forgone conclusion and has the structure/re-organisation already been determined?

Personally, if the re-structure hasn't already been determined - and even if it has to some extent, then I'd be thinking about small, inter changeable groups working on this new structure, being able to ask/answer questions and so on. Either way its an extremely large group to manage much on an interactive basis.

An ice breaker to start with would be a nice start - but for 400?? No idea. Where are you holding this event? In a football stadium?

Hi Emma,
Have you looked into going to GoApe at centre parks? You can hire out the canteen and then hold your meeting.
I'm sure they will give you discount as your such a large party!