There are numerous factors that can affect the progress of an application. How busy the processing office is, slow responses to overseas investigations, misplaced or lost files and so on. A polite query about the progress of the application would be in order at this stage.
A clause from our service agreement:
We will promptly inform you about significant developments in your case. If your case is not progressing in a timely and satisfactory way we
will let you know why this is so and what we are doing about it. Please note that various authorities might not respond adequately, or at all,
to progress enquiries.