MDX named Set for Financial Year

Current Financial Year

STRTOMEMBER("[Date].[Financial Period].[Year].&["+
  CASE WHEN CINT(Format(Now(),"MM"))  >= 4 THEN Format(Now(), "yyyy")
  ELSE CSTR(CINT(Format(Now(), "yyyy")) - 1) END + "]")

Last Financial Year

STRTOMEMBER("[Date].[Financial Period].[Year].&["+
  CASE WHEN CINT(Format(Now(),"MM"))  >= 4 THEN Format(Now(), "yyyy") -1
  ELSE CSTR(CINT(Format(Now(), "yyyy")) - 2) END + "]")