Sounds promisingWe could use the vaults actually good point - There is also several rooms above the mezzanine which can be used for conference rooms - We used to have erveything sperate but found much of the conference was being under attended as people would just hang in the expo all day.....
I think one thing people would move themselves down to the Vaults for is a free lunch and if that means the seminars can be moved to one of the other rooms upstairs (where the speakers can be heard better) that would be fantastic, imo. Would mean you could free up all that space on the balcony for seating where people can meet and chat over a drink
After that, the only remaining big problem would be to persuade UK "bouncers" to act like professional security guys. That's a bit more tricky...