@Goz I think your fit can work as either a shirt or shacket.
I've always preferred more fitted looks, but I have many IH pieces that all fit a bit differently. Several pieces have either started on the larger side or are still on the larger side after many wears. But what I can tell you is that I'm glad I've kept wearing each one because I appreciate being able to have different looks.
My reasoning to myself for keeping the larger pieces is usually "Well, I'll eventually gain a few pounds and it will then fit perfectly". But IH gear is just too good to not find a way to just make it work.