Fullscreen Betfair Video on Chrome
Install Stylebot
https://chrome.google.com/webstore/detail/stylebot/oiaejidbmkiecgbjeifoejpgmdaleoha?hl=en
Open "CSS" editor
Styles > "Add a new style..." > In URL pattern type videoplayer.betfair.com
Paste code from the Betfair CSS file in the code editor