Blazer coat arrived today and I must say that I am really impressed.
From what I can recall, the solid Navy feels thicker compared to the patterned navy. This is a good thing however as I will ultimately be wearing the blazer as a coat during FW.
Fit of the 40 is infinitely better than the 42, even if it does now feel a little tight in the shoulders. Sleeves are also a tad long but that's a very simple fix - about half an inch or so will do it.