Our SUM License expired, and the URL that we used last time, now takes me to an XG Trial page rather than the page to 'Register SUM and get a license key.' 

Does anyone have a better link?

(Below is the link I was trying to use from: https://www.sophos.com/en-us/support/utm-downloads.aspx%C2%A0)

Sophos UTM Manager

A central management application lets users see and work with all Sophos UTM products through a single login. You can access the full ISO below. Sophos UTM Manager requires a license after 30 days, but you can request the download link, installation guideline and a full license file in a complete package by filling out our web form

Register SUM and get a license key