I only seem to get the US version but I speak English, not American (the difference is considerable - same words, different meanings!)
If you told the operating system and version of LibreOffice someone could point you to the exact language pack file to download.
Please edit your question to provide details, do not use the Answer field. Thanks.
Or search the forum.
If you keep downloading the US version then I suspect that your computer or your browser is set to English US somewhere. In your Windows taskbar at the bottom of your screen at the right, there should be ENG visible, click on it. If the Language and keyboard at the top of the list highlighted in blue, are not English UK then clicking on the correct one might fix the settings for you (or might not, language settings are all over the gaffe in Windows).
Otherwise, click on Language Preferences, in the dialog window, change your display language to English UK, in the next paragraph down you want English UK at the top (default), if it isn’t click on the link “choose and input method to always use as default”. It should be self-explanatory but check all the settings further down too. I had a Windows Update about 6 months ago that changed all my settings to English US (again!)
Check your browser too, in Firefox
Tools > Options > General > Language has a setting to change to English UK.
If you meant version 7.0.1
Here you go. Mind the Architecture
Wasn’t it that the Windows installer contains all major language packs so it would be a matter of just invoking that again and add an UI language? At least that was the procedure, not using Windows myself I can’t tell for sure. The offline help are separate packages.