Possible Clues:

• __ Britain (London art museum)
• ___ gallery
• London destination for Turner fans
• Comedian Catherine
• Four art galleries - in London, Liverpool and Cornwall
• Home for a Hogarth or a Constable, with 'the'
• 'The Office' star Catherine
• British 37-Down institution
• ___ Britain (art gallery)
• One of four art galleries in England