Looking at the video clip, it seems to have been taken on Jan 27 1965, at which time there were 6 4F's allocated to Barrow Road : 43924, 44135, 44264, 44269, 44422, 44466. The engine used on the mail would almost certainly have been a Barrow Road 4F and Standard Tank. As Ralph says, 43924 was RH drive. Here are some photos of the six engines showing whether they are left or right hand drive.We are pretty sure this is 43924 for not only is it RH drive but there is a large oblong rusty patch on the RH tender side above the beading
43924 http://www.flickr.com/photos/8755708@N07/6823913966/
44135 http://www.flickr.com/photos/the-evanses/4996075423/
44264 http://www.flickr.com/photos/curly42/6105893982/
44269 http://www.flickr.com/photos/bristolste ... hotostream
44422 http://www.flickr.com/photos/bristolste ... 5776010012
44466 http://www.flickr.com/photos/52467480@N08/6435901339/
From the photos it appears that 43924 and 44135 were RH drive (I am not an expert on this).
Although the number of 44135 is not visible, other photos of the engine show it to be identical.
Although both engines were active around the above date, the rust patch on the tender points to it being 43924.