There really is a lot of purely theoretical stuff written about what Meta Tags can and can't do for your site. I would suggest anybody interested in them should take a close look at http://searchenginewatch.com/webmasters/article.php/2167931 . That clears up a lot of the questions. The rest of that site is full of interesting - and relevant - items about optimising your Head Tags.
As for putting UK, location etc - the Keywords you use are the most actively searched parts of web pages, so drop those words in there. Of course, if they are in the first few hundred words of your page, that will help too as search engines can ignore keywords if they don't find matching words in the Body.