The e-commerce behemoth provided the 189 documents required by the Competition and Markets Authority (CMA) after the deadline, which the CMA said caused unnecessary delays to their work.
The purchase was cleared in August, 16 months after the £452mln fundraising was first announced, as it would not damage competition in restaurant or online convenience grocery delivery.
Also on Monday, the UK arm appointed John Boumphrey as the new boss to replace Doug Gurr, who is stepping down.
Boumphrey has been at the company for nine years and is currently vice president of Amazon Fashion Europe.
Amazon is creating 10,000 new permanent roles in the UK in 2020, taking the company’s total permanent UK workforce to over 40,000.