I think your dead right regarding the 225/45 x 17 that goes on the Excel and maybe the Design trim.
But our one has 195/65 x15 tyres on it (Icon Hybrid), which doesn't get the directional label. On the newer Icon, Icon+ and Business Edition models there would be 205/55 x16 fitted. Another of our cars has that size, I didn't think that has any arrows as it's a tyre size with no performance pretensions, e.g. found on older, lower spec. Mondeos and Focuses. So yes, certainly worth looking at the label before you go ahead to change them!