TM has a separate (EXCELLENT) department that handles business accounts. You should have a particular person assigned to handle your account.
Hey ajthou! I'm so sorry to hear you're not able to connect to the roaming partner you're accustomed to and that you're not having the ideal experience you've grown to expect. Since multiple colleagues with your company are impacted, I'd forgo standard troubleshooting and encourage you to reach out to a team with account access ASAP so that we can take a deeper look.
You can reach us while roaming internationally by following these instructions. A tech support team can review the roaming partners in the area of the UK where you're located and if necessary, file a ticket so that engineering can report back with insight on whether this is a temporary change due to an outage with the roaming partner or a long term shift in roaming agreements. We definitely want to get you all the info we can!