Last Collection Times Post Office Dartford. This post box is emptied from Monday to Friday at: 18:15. A Dartford Postbox Latest Collection is made at 18:30. On Saturdays the collections are made at 12:30. There are no Sunday collections from this Postbox. The post from most other Postboxes during the week are collected more or less at the same time with a small time difference of approx 30 minutes. On Saturdays the the difference in collection times differ more significantly. To check the Saturday collection times read the related posts listed below.