user: Question: When was the first UK broadcast for the episode with an official TNS Gallup rating of 1575000?
Columns: ['Episode', 'First broadcast Denmark ( DR1 )', 'Official TNS Gallup ratings', 'First broadcast UK ( BBC Four )', 'Official BARB ratings']
Types: ['real', 'text', 'real', 'text', 'real']
Sample row: [1.0, '27 September 2009', 1702000.0, '19 November 2011', 1248000.0]
SQL:

assistant: SELECT "First broadcast UK ( BBC Four )" FROM "Table" WHERE "Official TNS Gallup ratings" = 1575000.0;