To add to your point about the USA, how many trade tariffs tend to apply to service-based companies with a tech focus (i.e. the majority of tech startups)?

From what I've seen, the answer is pretty much none. So long as barriers to tech talent aren't put in place, there's basically nothing holding back the UK tech scene. The fear being generated by the media (along with those that repeat those fears without critical examination) is more damaging than the situation as it stands today. We're talking about something that only happened within the last few weeks, the sky isn't falling, it's all a failure of perception.