The fierce competition for training places generates a vicious circle whereby LPC students, such as myself, cannot feel safe writing just to those firms we would like to join, for fear our applications may fail to stand out among the 800 - 1,500 others that an advertiser may receive. So as 'insurance' we feel obliged to write to another several dozen mutually less suitable firms, thereby feeding another round of congestion in the system. Nobody benefits except the Post Office.
Might I suggest that when each CPE student/law finalist enrolls as a student member of the Law Society, they are sent 25 sticky labels. If a firm receives an application bearing one of these, they will know this is a serious candidate who has a real preference to work there. Those still without a job by the next Easter might apply for a fresh supply of labels.