CAP 413 adds to the confusion by giving an example of traffic information being passed as G-CD, traffic is a Cherokee upwind and a Tomahawk late downwind. Perhaps this is what you are querying. In this case, where is the pilot supposed to look for the Tomahawk - on climb-out, crosswind or even at the start of the downwind leg before reaching the downwind report position? I have drawn this anomaly to the attention of CAA but am not holding my breath.
I'll start my Sunday morning a little cheeky; I think you meant where is the Cherokee in your example. The CAA might give a confused look at your query if you ask where the Tomahawk is and take that in the amused tone I send it. I agree though; there are some doozy terms in CAP 413.
When joining the circuit for the active runway to land, and approaching from non-active side of the pattern that is deadside why should we call this Upwind as when departing the active runway for a circuit or departing the field this is called Upwind?
As for the question, the answer depends upon where you learned your initial flight training and where you are flying.
This diagram describes what you learn in the UK (from CAP413):
This diagram describes what you learn in Canada or the United States (from the FAA Aeronautical Information Manual as obtained from
Air Facts with a notation from me about the wind direction):
So, depending on where you are geographical, either of the terms is correct.
In almost 20 years flying, I've found our beloved industry is
notorious for people sharing and teaching their opinion of how things should be, rather than how they are. In this case, both terms are correct for different situations. Dead Side is not appropriate in Canada or the U.S, whereas upwind (or non-traffic side) is. Likewise, Upwind is not appropriate in the UK as Deadside is used to describe the same position.
It's akin to calling the landing gear the undercarriage. Some will pick a hill to die on over that debate!
It is simply a lack of knowledge, sometimes bordering on laxity, that comes from exposure; that is, most flight instructors train just in their jurisdiction so only know what they've been taught. Then, they get a student who either learned it a different way or is reading from a book published elsewhere, and that instructor will tell the student they are flat out wrong. The student is not wrong, given the proper context.
And a fact without context is just a belief.