I am dealing with your UPS problem and am awaiting our technical department and will advise as soon as I have a response. Please remove Adam Parker from any future communications.
We have looked at the photographs and notice that the inverter is showing an output current but no voltage, this would normally indicate a short circuit on the output of the inverter, also it sounds like it is in overload. Can you measure the output with a voltmeter please? Is the site easily accessible and manned if we need to ask any further questions?