Problem introducing UNICHAR

I want to put up and down arrows on a set of data.

I start simple

Arrow = 
SWITCH(TRUE,
        [This Week] > 0, "Up",
        [This Week] < 0, "Down",
        "Side"
)

and I get the result I expect.

Then I try

Arrow = 
SWITCH(TRUE,
        [This FY] > 0, UNICHAR(11165),
        [This FY] < 0, "Down",
        "Side"
)

and I get the result I expect

Then I add the other unichars

Arrow = 
SWITCH(TRUE,
        [This FY] > 0, UNICHAR(11165),
        [This FY] < 0, UNICHAR(11167),
        UNICHAR(11166)
)

and I don't get what I expect to see

I also tried the below but got the same result

Arrow = 
VAR Up = UNICHAR(11165)
VAR Down = UNICHAR(11167)
VAR Side = UNICHAR(11166)
RETURN
SWITCH(TRUE(),
        [This FY] > 0, Up,
        [This FY] < 0, Down,
        Side
)

What am I doing wrong?  I've read through a fair few threads on Unichar issues and can't see where I'm going wrong.