The battle is known as either the Battle of Deptford Bridge or the Battle of Blackheath, and this dichotomy is at the root of the rebels' loss, for the forces were split, with a group left guarding the river crossing at Deptford, whilst the rest camped on Blackheath. As the King's forces approached from central London, they met the isolated force at the Bridge first, and quickly defeated it. Once this had happened, with the rebels in disarray, the battle was all but over. Those left on the heath were soon defeated.
For more, see http://en.wikipedia.org/wiki/Cornish_Rebellion_of_1497