You're formula is missing a comma separating the test condition from the True argument in the IF function.
="Q" & CHOOSE(MONTH(A2),4,4,4,1,1,1,2,2,2,3,3,3) & IF( MONTH(A2)<=3,"FY" & " " & (YEAR(A2)-1) & "/" & RIGHT(YEAR(A2),2), "FY" & YEAR(A2) & "/" & RIGHT((YEAR(A2)+1),2) )
Fix that, and your...