user: Question: What is the release date of the Bonus interview with Peter Purves?
Columns: ['Story #', 'Title', 'Doctor', 'Narrator', 'Format', 'release date', 'Notes']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [37.0, 'The Tomb of the Cybermen', '2 Second Doctor', 'Hines, Frazer Frazer Hines', '2-CD', '2006-05-01 1 May 2006', 'Bonus interview with Frazer Hines']
SQL:

assistant: SELECT "release date" FROM "Table" WHERE "Notes" = 'Bonus interview with Peter Purves';