Citroen Berlingo map screen flicking between day and night

I have a berlingo van ( brand new 25 plate) and the map screen is driving me nuts. It switches from day ( bright) to night (dark) constantly for no real reason. It can be bight sun , clear sky and boom , its dark screen ?! And if I activate the wipers the screen flicks dark for a second...Thing is whilst its doing this the head lights are also going on and off !!
Surely this cant be right ?
I took it to Wilmoths in Maidstone and whilst the receptionist initially said it sounded like a problem and that it "cant be right" ( suggesting to me its something she hasnt been aware of) , the tech guys in the workshop insist its normal and happens on other citroens .

Have you heard of this ?
Rob