Seems a lot is being said here. I can confirm that admissions (those who look at applicants portfolios) value Art above any other subject, primarily as it teaches the fundamentals of process, exploration and critical thinking.
Design is also a good subject (aka graphics) I think it develops very useful skillsets, however, admissions tutors prefer art applicants.
Best three subjects at A-level to study for architecture are: Art, Physics and Maths. If art is not an option (which was the situation for me), DT is the next best (it is also a bit less stress-filled).
Ultimately the portfolio matters most, so a really strong portfolio can bypass most of the requirements/ subject recommendations. However, that is very risky.
If you feel like you require extra skillsets before studying Architecture, I highly recommend you then do a year of Art Foundation or Art and Design Foundation.
I used to mentor architecture students and I occasionally give public talks on applying to University/ architecture jobs for fresh graduates. So I have some experience in this area.
Hope that helps!
If you you have further questions, please feel free to send a message.