I think that your best bet is to zoom to an optimum view, close all of the pop-up windows and make a screenshot. You can order pdfs of individual old OS maps (not side-by-side views), but in my limited experience they are of rather low resolution: screenshots of the high resolution online view will be better, and free!
Also note that you can change the modern view between various options: I left it as a satellite view because it clearly shows that the farm isn’t there any more.