The time displayed in the Notebook is the actual time as per your time zone (BST) whereas the queue shows the time with the message Sent Date UTC (which is 1 hour behind BST) so the 2 times are in fact the same.
This article provides an explanation as to why the sent time in the Notebook and Mail queue is 1 hour different.
The time displayed in the Notebook is the actual time as per your time zone (BST) whereas the queue shows the time with the message Sent Date UTC (which is 1 hour behind BST) so the 2 times are in fact the same.