That is right history is written by the victors.
However, as time goes by, more research is done. Private papers are researched and they reveal many things that were not brought out by those who wrote history.
One thing one has to give it to the British is their sense of history. Like the works of Tod on the Rajputs or Lawrence on the Kashmiris or Moorrecroft also on Kashmiris of Younghusband. They maintained diaries and these diaries were preserved by their descendants and then archived.
Unlike what is written of Lord Wellesley, the private papers of many to include General Palmer, Russel, Kirkpatrick gives an insight how many British (mostly those who married Indian ladies) found Wellesley an arrogant racist, self opinionated and a disaster that ruined the comforting ambivalence with the Indian native states and with the Indian gentry. Wellesley's imperialistic attitude caused great woes to the British when they took on the Marathas.
Therefore, with the new research, history can be addressed more close to reality of those times,