TFS Pull request bad URI

Resolved sonar.core.serverBaseURL not set

I’m using SonarQube 7.4 developer version, TFS 2017 update 3 and 4.4.1 of the SonarQube TFS plugin.
Both TFS and SonarQube are on the same server, with a different port - I think this is the cause of the problem.

All my analysis runs correctly and the pull request is visible in the sonarqube branches window with the correct isssues identified however the pull request isn’t decorated.

Looking at the logs the following error message is displayed: