After the Battle of Pavia Henry VIII tried to use the opportunity to revive his kingdom's claims to France. In real life the Holy Roman Emperor essentially replied "Go stuff yourself, you whiny little second-rate power," but I suppose that if Henry's England had acquitted herself better in the previous years' campaigns, Charles V might have agreed to support Henry's claims to Aquitaine, Gascony and Navarre, since these areas had been under English rule for most of the Middle Ages, and giving them to Henry wouldn't upset the balance of power in the same way that giving him the whole of France would. As for the Low Countries, I think the Dutch rebels offered to make Elizabeth I Queen of the Netherlands, so if she accepted we could see this area come under English sway as well. Of course, this would be a dynastic union, and even if England managed to hold onto them (which is by no means certain -- at any rate, I can't imagine the French monarch being happy with losing large swathes of his territory, and England probably didn't have the resources to defend them against a determined French attack) it's quite difficult to see all these territories being welded together into a proper United Kingdom. Perhaps if these territories all end up converting to Protestantism we might see them uniting to better combat the Catholic menace (something similar was actually proposed in the 1650s between England and Holland). Possibly, too, the English monarch might offer the Huguenots aid in return for their recognising English rights to Aquitaine et al., so, if the Huguenots end up winning/forcing a better deal than IRL, that might provide a way for the English to keep hold of their continental territories.