OK, just to conclude this. I have now, after my test shirt, finished my first wearable shirt! The Pattern (McCalls 6044) called for a large but it did turn out a bit baggy(don't know why I didn't realize this when trying on the test shirt). Anyway this was I suppose a good thing as it's taught me that with some careful unpicking it is a pretty easy job to tailor. I bought the buttons, which are made from olive wood, and was really pleased with the overall look.