The Bumptious Gastropod was a dining experience outside the universe and outside spacetime. Hence, the usual rules of causality did not apply. It was the place where the Doctor died according to the Kovarian Chapter (AUDIO: My Dinner with Andrew) after the Doctor survived the events of Lake Silencio. (TV: The Wedding of River Song, The Doctor, the Widow and the Wardrobe)
When it was still a café, it was bought by Andrew Edwardson using an unlimited credit slip from the Galactic Century Bank. Customers could order dishes such as poached leg of Mire Beast and Rutan Roulade. (AUDIO: My Dinner with Andrew)
After failing to assassinate the Fifth Doctor using Aqua Galatia in 18th century Venice as requested by Madame Kovarian, Brooke met Kovarian at the Bumptious Gastropod. (AUDIO: A Requiem for the Doctor) River Song switched the Doctor's clothes with Andrew, who closely resembled the Doctor. Brooke killed the Doctor using regeneration inhibitors. (AUDIO: My Dinner with Andrew)
However, Broke eventually went back in time and convinced Andrew to take the Doctor's place. (AUDIO: The Furies)