After my 20th visit in a month, I finally realised that you can host your event in National Museum of Scotland. What I also found out is that not only do they have a mountain of different function spaces, you can be flexible to do any setup you require.
I dabbled on their amazing dinners and receptions, where they can host 950 guests for dinner in their exquisite Grand Gallery. This is their largest dining area, which from my experience provides a creative and unique environment for any black tie event. Photos below. The best thing about this venue is the choice of Approved Caterers who provide an array of cuisines.
Do check out their website for more details!