Have you removed and reinstalled the web browser your using reset the web browser cookies etc Safari or chrome?
The one that you use to access the site if not i would uninstall the browsers and reinstall, restart the phone and check google maps works as expected, then open www.wildcamping.co.uk and go to the location app and see what happens.
There are two places where Safari's access to your location can be disabled.
Please can you look at:
1) Go to settings
2) Scroll down until you see "Safari" this is not with the other apps it is in the same section as "messages".
3) Look at "settings for websites" and click on "location"
4) Please make sure this is set to "Allow" or "Ask"