Solved this problem - the fault was in the default settings in the EXE.XML file. There are two things to check if this happes to you. 
1. Ensure that each entry has its 
ManualLoad set to 
False2. Ensure that the 
Launch.ManualLoad setting at the top of the file is also set to 
False. 
Code:<SimBase.Document Type="Launch" version="1,0">
  <Descr>Launch</Descr>
  <Filename>EXE.xml</Filename>
  <Disabled>False</Disabled>
  <Launch.ManualLoad>False</Launch.ManualLoad>
  <Launch.Addon>
    <Disabled>False</Disabled>
    <ManualLoad>False</ManualLoad>
    <Name>GoFlight Hardware Interface</Name>
    <Path>C:\Program Files\GoFlightFSX\GFDevFSX.exe</Path>
    <CommandLine></CommandLine>
    <NewConsole>True</NewConsole>
  </Launch.Addon>
</SimBase.Document>
 
All the best
Ian