Shibboleth 2 and ports

[danbuntu]

I've just set up a Shiboleth 2 IDP using the Janet Windows quick installer (well I say just - it's taken me ages)

 

I seem to have one final niggle. When I go to the Janet test site and click on my link it forwards me to http://myentityid:80/shibboleth

 

the problem with this being that it's not running with ':80' (if I edit the url it works fine).

 

I've been picking through the config files and I'm blowed if I can find out where I change this. Does anyone have any ideas?