Congratulations Stu on a very fine purchase.
I feel your pain about the damage caused by the carrier, hopefully proper compensation is made and you can get this beautiful machine back in 1st class working condition.
Your hydraulic mixes, I'm not familiar with the Premacon models, but I do believe they use the same 0,3ml/rev Jung pump that my Fumotec models use with a big brushless drive motor? The initial Amp draw just to start that brushless motor continually will create excessive heat build up within your esc & then the thermal protection will kick in & time out the esc till it cools. It's better to have at least 20% motor activation at all times of intermittent digging. Shut the pump off via a switch when the trk is full.