Maybe I can contribute to this discussion. I live in Brazil. The site's domain extension depends on the country or region that your business serves. I recently worked on a project to create two different sites for different countries.
In Brazil, it is recommended to use the .com.br extension. It is the first and important signal to Google that my website is targeted to Brazil.
However, we have created another site with a .com extension only, for which the company's focus was also to the United States, and opened new website designed just for this audience. .com But is still very wide. In addition to having created the
PressCell site, the source put http-equiv as en_US, but targeted English language to the North American country. Also in the code I worked with
href lang, pointing in the English version of the existence of a page translated into another URL. Example.
In English page has the
<link rel="alternate" hreflang="en_US" href = "http://presscell.com.br/voz-vozdados/" /> and vice versa.
If your intention is that the site is targeted only to the UK, then the extension is .uk. Otherwise, have more English-speaking regions, more information in the code must be entered as the particular example I showed above.