Your boiler is currently running a specific commissioning program typically used during installation or testing, meaning it is not in its normal operating mode.

DIY fix possible

Press the 'Back' button (left arrow) on the control panel to see if the display returns to the standard pressure/temperature reading.Turn the boiler off and back on at the main isolation switch (fused spur).Wait for the program to finish its cycle, which usually takes about 15 minutes.