in the search bar, if that's its proper name, type in; google.co.uk. You'll come to a page with a list of google options. Click on the top one which should be google.co.uk which offers UK-specific pages.
at the top right of the screen there should be three symbols. A little house, a star, and a cogwheel. Click on the cogwheel. A drop down menu will appear. Click on 'Internet options'.
A window will open and in a box under 'home page' type in the address you want as home page.
Below that there are 3 boxes. 'Use current', is the one you need to click on. Finally click on 'apply' at the bottom of the window.