Good morning, my name is ***** ***** I will assist with your query today.
This fault is most likely a faulty PCB, which controls the output to the display, this can be sourced here for around £200.
To verify it is this part at fault its a case of stripping the unit down, checking all the ribbon cables are in place, then checking with a multi meter power is getting to the key parts of the board.
Due to the likely cost of the part its probably worth looking at a Repair and Protect plan from D&G rather than paying for an engineer to attend.
Please let me know if I can be of any further assistance, please provide the age the appliance and your postcode if you would like me to recommend a suitable R&P plan or local engineer.