I don't have an issue with Brunel or Churchill being in the list or even being well placed on the list but when you measure them against the entire history of the land I am not sure they would be given the positions they have attained.
When you have the likes of Newton, Shakespeare, Darwin, Nelson, Wellesley, Scott, Drake, Livingston and countless others who have made huge contributions to the world through their actions I am not sure Churchill or Brunel are really top 10 material and I am damn certain Diana isn't even top 1,000,000 material.