Corporal Heron was a low-ranking officer in the animal/human battles on Winkle's Wonderland.
While dealing with the aftermath of the explosion of anti-time, the TARDIS created a series of holographic projections, taken partly from reality and partly from the memories of the Eighth Doctor, Charley Pollard and the TARDIS itself. One such projection was the battle in Winkle's Wonderland as the TARDIS was looking for information on the Divergence. Inside this projection, it placed Charley in the role of General Mouse and itself in the role of the Captain Dodo. The projection of Heron was created using the voice of the Seventh Doctor's companion Jason Kane. (AUDIO: Zagreus)