Can anyone recommend a great London venue for a reception and dinner for approx 80-100 people aged 25-40? Needs to be very good quality. Preferably not restaurant or hotel - maybe an institutional or private members' club type of venue.
You might think this an odd suggestion, but have a look at the English Speaking Union building (Dartmouth House) in Mayfair. Sounds worthy & institutional but it's a beautiful building, very central, and it's catered by Leith's.
Museum of London? Actually most of the museums will hold functions You get to party amongst teh exhibits then they normally have a big space where you can eat.
London Dungeon is another good one - the ride is very scary when you've had a few drinks. Do you wnat something a bit different like taht or just a posh black-tie type thing?