Edwardian postcard by F.G.O. Stuart of Presentation of New Colours by H.M. The Queen

Unknown Location! I've been unable to find this location.
Do you know where this is?

London Queen Victoria Royal Family Unknown Location

Number:: 26
Title:: Presentation of New Colours by H.M. The Queen
Details:: I assumed that this would be at Horseguards but none of the buildings seem to match. Please let me know if you know the location.
Print Origin:: Hudson & Kearns
Print Type:: Screen Block
Print Tone:: Black & White