As suspected, the Wavelink Avalanche installation program has installed its own copy of postgres, however it installed the databases onto the existing postgres database server. You can see in the following picture, that postgres 9.1 (the version that comes with avalanche) is installed, using the non-default port of 5433. The servers existing database server, version 9.3 contains the avalanche databases.
I have since uninstalled postgres 9.1 and Wavelink shows no signs of issue.
