Possible Clues:

• Palace of bliss for souls of slain heroes in Scandinavian mythology
• Small room's back entrance leading to a place for those bravely turning up late
• V&A library originally next to foyer -- a blissful spot
• Odin's place
• In Norse mythology, the great hall of Odin where heroic warriors dwell eternally
• Scandinavian paradise
• Vikings' afterworld
• Where Odin receives heroes slain in battle
• 'In Norse mythology, the hall in which the souls of heros were received by Odin (8)'
• Wagnerian setting