Hi Everyone,
From the github issue above I found a workaround that works well for me, so I’ll post it here in the hopes it helps someone.
Hopefully in the longer term this auto-update of the drivers will be added into SeleniumLibrary 
First I create this resource file:
SeleniumDrivers.robot
*** Settings ***
Documentation These keywords need the webdriver-manager module
... pip install webdriver-manager
... https://pypi.org/project/webdriver-manager/
*** Keywords ***
Update Chrome Webdriver
[Documentation] Update Chrome Web Driver
${driverpath}= Evaluate webdriver_manager.chrome.ChromeDriverManager().install() modules=webdriver_manager.chrome
[Return] ${driverpath}
Update Firefox Webdriver
[Documentation] Update Firefox Web Driver
${driverpath}= Evaluate webdriver_manager.firefox.GeckoDriverManager().install() modules=webdriver_manager.firefox
[Return] ${driverpath}
Then in my robot file I include it and call the keyword for the driver I need in the suite setup like this:
*** Settings ***
Library SeleniumLibrary
Resource SeleniumDrivers.robot
Suite Setup Update Chrome Webdriver
*** Variables ***
This way the driver update check will get called before your tests and Open Browser so hopefully no more failed tests
Hopefully that helps someone,
Dave.