Took me a while to realise that you don’t need to go through the whole reinstall an OS task sequence if you just want to retest a software install that failed within an MDT installation.

Make sure that a new Task Sequence is created on the MDT server that installs an application. Then once the OS has been installed you can just connect to the mdt server deployment share and run litetouch.vbs.  Provide the credentials and test the installs.

Unfortunately I can’t work out why most of my installs are failing with unexpected error 2.