When Henry and Thomas leave Tidmouth Sheds together, Henry's wheels are moving backwards. Additionally, Henry is still laughing, even though his mouth has stopped moving.
Thomas' London, Brighton and South Coast Railway number is 70 to commemorate the 70th anniversary of the Railway Series, but the E2 numbering ran from 100 to 109. Also, Thomas would have likely been painted in the LBSCR's Marsh umber livery (a dark brown) and not teal.
When Edward says "It's not as easy as you think, Thomas!" the points he's going over are against him and a crew member's hand is emerging through the wall of Edward's cab.
In a close up of Gordon as James goes past him, James' tender is in his red livery.
Henry was not in his original "pre-Flying Kipper crash" shape, even though that the events of TAB take place before those of The Flying Kipper.