I have just discovered ‘quiet mode’, that limits the initial peak demand of Watts (throttling the output), in our case max 1.1kW (I keep the pump unlimited (starts at 24l/min then reduced to 7l/min), so not to effect the logic or option/triggers in the HP), its ok for our house as we do not need the full capacity of the 8kW unit, one side note I have had to increase the off peak DHW heat schedule as it takes longer to heat up the cylinder 
Hope this helps others smooth out the initial power draw getting to a steady state faster while increasing efficiency?
Thanks to -