Please help me to solve this

Robin was shovelling snow from his driveway last winter, pushing snow to the side of his property in order to clear a path for his car. His neighbour, Dave, came out and angrily asked Robin to stop, as Dave felt the snow was falling onto his property. Dave proceeded to push Robin away. An argument ensued, resulting in Dave pushing Robin onto another neighbour's property. Analyse this case with regard only to the tort of trespass to land, in the format used in the course