I am from the UK, but a lot of the questions on the site are from the US. Is there a convention for asking UK specific questions?
Yup. Questions that might be localized to a country or region should start with the right tag.
Here are the top 5 country tags on the site, right now:
n.b. Questions that aren't country-specific won't have a country tag, so you'll also find a lot of questions on the site that may be relevant to somebody in the U.K. but not tagged united-kingdom.