Set Appliance State:

CH Demand
Boiler CH thermostat set to MAX
Ensure appliance is set to WINTER mode - NO sun symbol in display
(Press reset button briefly to toggle sun symbol on and off)
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

The boiler is preset with a 2 minute delay before it will recognise a heating demand after a DHW demand.
(d1 or d2 may be displayed during this time these are not fault codes)
Central heating demand is indicated by 3 small lines flashing above the radiator symbol and the °C symbol appearing in the display.
Does the boiler recognise the central heating demand?