In many cases there are a lot of numbers and letters on windows, this can make it difficult to identify which one to provide to someone in order to get the correct replacement.
Here is a quick guide:-
Polyplastic manufacturers window stamp
These details are classification numbers and do not give any information about the window.
Part number window sticker
Caravans from 2013 onwards have a sticker which indicates the actual window part number. It is located on the rear of the window rail (windows will have to be open or taken out to get this information).
Dometic Seitz Windows
Dometic Seitz windows have this sticker in every window it has the make, size and model even on the newer design you will still see this label or something similar.
However if the Dometic window is missing then there will be a size stamp in the left hand corner of the frame itself.