This view is cropped from the opening seconds of the film Devil Girl From Mars. Within the film narrative, this one was supposedly carrying passengers over the Scottish Highlands in the then-present-day, which turns out to be 1954.
If you can help me with the type, I can find most of the other information I need by myself. However, I would also be interested to know
(a) whether there is anything to be discovered from the barely-visible markings, and
(b) if it's possible to tell whether this shot represents a particular model of the type in question, and what that might say about the background of this specific machine (regardless of context in the film).