Confirmed HERE, even though they have the capacity wrong.
Twickenham (Hosting 8 games inc. final, capacity 82,000)
Millennium Stadium (8, 74,500)
Wembley (6, 90,000)
Kingsholm (4, 16,500)
King Power Stadium (4, 32,262)
Amex Stadium (3, 27,350)
Villa Park or Ricoh Arena (3, 42,788 or 32,609)...