Typical of the last week or so of work for me it doesn’t look like it was entirely what we were expecting, the fusible resistor was not blown and listening carefully I could here a repetitive peep from the display board indicating that the power supply was stuck in a restart loop, having had a slightly deeper look at the pcb on the bench tonight I have found that the SMPS chip is fine and that I have only need to replace one shorted diode (D7 on the output side of the SMPS transformer) and now have 5V running round the board. Tomorrow I will refit it and confirm if that is all that was wrong.
Jem