Right, I've fixed it.
Add the following to SolarWinds/Orion/Information Service/3.0/SolarWinds.InformationService.Sevice.exe.config
~
</system.web>
<system.net>
<defaultProxy enabled="false" />
<settings>
<httpWebRequest useUnsafeHeaderParsing="true"/>
</settings>
</system.net>
<log4net>
~
Add the system.net between the system.web and log4net configuration sections