don't know if the management company can put down yellow lines or not, but from my experience as a board of management member in our local boys primary, cars will park anywhere there is space outside a school, we have had in this order, yellow lines, yellow box, flashing amber lights with a pedestrian crossing, and finally the council recently raised the crossing on the road to a speed bump type of crossing and now the cars just stop on top of the speed bump oblivous to all around. best of luck !