The page at https://gaviscon.com/ says:
You are now leaving Gaviscon.com and moving to an external website independently operated and not managed by GSK.
THIS SITE IS INTENDED FOR US RESIDENTS ONLY. GAVISCON ® IS A TRADEMARK OWNED BY OR LICENSED TO THE GSK GROUP OF COMPANIES.
©2017 GSK GROUP OF COMPANIES OR ITS LICENSOR. ALL RIGHTS RESERVED