Booking error!

Hi i booked my flight independently last month to fly out to dalaman for october,The problem being when i entered the names of persons flying i put my partner name down as Dave instead of David which is on his passport. I am not sure if this will pass through check-in or passport control.I did email the flight broker and they seem to think that it will have to match the name on the passport ie (David),To change this they want £50
Has anybody else shortened there name,if so was there any problems... Many thanks
