Darren. When you have finished work today......remove the fitting from the end of the hose that goes to the truckmount and place in to a bucket. Making sure the header tank is not full, Switch on the water pump and time it for 1 minute. Then measure how many litres of water are in the bucket. The demand pump on your machine should be giving approx 13 litres a minute.
I just spoke to Woodbridge and they said they have spoken to you and explained about the fuses. So, lets try and eliminate......remove the fuse that has the Brown or Black wire going to it. Run the machine, if it still cuts out then repalce the fuse and remove the fuse that has a Orange wire going to it. Again run the machine if it still cuts out replace the fuse and remove the fuse that has the green wire going to it. Run the machine, if it still cuts out give me a call. So, if when removing any one of the fuses it does NOT cut out we will know where the problem is......
Theres a few things it could be but the most obvious / likely one is the demand pump and the tech at Woodbridge agrees.