Batchy, it was 1899. By this point Pilcher had been experimenting on and off for 5 years. The question of what Pilcher might have achieved is a matter of personal judgement, speculation based upon what we know of his previous performance. My judgement is that from 1894 to 1899 Pilcher made a modest contribution to aviation but demonstrated nothing to suggest he would be capable of the huge scientific and intellectual breakthroughs made by the Wright Brothers in the period 1899-1905.
I do believe there is something Darwinian about the Pilcher story. He did indeed work on a trial and error basis. In trying hard to succeed, he learned the hardest lesson of all.