Mixture is extremely complex with a lot of different tobaccos. It's sweet because of the cavendish and virginias, but also sour from the kentucky and possibly some oriental. Mild and rather low on nicotine.
Navy Flake is very burley forward. There is a topping of rum and honey or molasses, and then there is the nutty burley with some musty sourness. Nicotine is medium or even a bit more than that.
I think they are very different blends, but both very Mac Baren.