It doesn't change the fact that the teams I mentioned purchasing licences for nationalistic reasons like Mercedes-Benz
Do you honestly think that Mercedes' decision to compete as a German team has to do with German nationalism? Or is it because the team is wholly owned by Mercedes-Benz, globally recognised as a German car manufacturer?
Teams base themselves in Britain because that's where the knowledge and expertise is to be found. That's where the suppliers are based. That's where the infrastructure is to be found. Being based in Britain means running out of Heathrow and Gatwick, two of the most accessible points on the face of the earth. Say I want to set up a team in Australia and compete as an Australian team. Every single race (except Melbourne) becomes a flyaway race then.
Look at Toyota - one of the mistakes they made was to set up in Cologne. It was where Team Toyota Europe were based, but they had trouble attracting staff and finding suppliers. The same thing happened with USF1, who established a forward base in Alcañiz.
I have heard England referred to as motorsport's Silicone Valley. And I think it's an apt comparison - the knowledge, resource, supplies and experience are all there. If you were a new team, why wouldn't you set up there? But if you do, you shouldn't be forced to identify yourself as British.