Wow I can answer. I'm going for the Portuguese side. One of the most important moments of this alliance happens during the invasions of Portugal by Napoleonic forces because, being an ally, refused to participate in the naval blockade against the British. At this time the alliance became a dependency. Portugal was invaded three times, the monarchy fled to Brasil, and the defense was in charge of English officials. You can literally see the impact of you visit Porto. The British are very keen on Port wine, so the region of the Douro river valley, became an almost exclusively English trade. The barrels were transported by ship, and the city sits at the end of the river, with the south bank ponctuated with warehouses billboards written in English. Because of this trade and its strategic importance the city started to grow exponentially since this time, with major changes to city planning occurring around this time. From an English garden, to busts of the duke of Wellington, and my alltime favorite: the duplicate of the crystal palace used in the 1865 International Exhibition. Maybe in the English side, apart from Portugal taking part in the invencível armada due to being Spanish at the time, it's the probably about the wine, but that I have no idea, just speculating a bit. Ain't got no further reading right now, I'm on the phone. I'll check when I get home