Who is the sole recipient of both the British Victoria Cross and the German Iron Cross?

Surgeon General William Manley

On 23 September 1864, he received the Victoria Cross for "his conduct during the assault on the Rebel Pah, near Tauranga, New Zealand, on the 29th of April last, in most nobly risking his own life" during the Waikato-Hauhau Maori War, New Zealand.

In 1871, he was awarded the Iron Cross 2nd Class for Non-combatants "for services with the British Ambulance Corps caring for the wounded of the 22nd Division in the actions of Chateau-neuf and Bretoncelle, on 18th and 21st December 1870, and the battles of Orleans and Cravant, on 10th December 1870" during the Franco-Prussian War where he served as a member of the British Ambulance Corps which was attached to the 22nd division of the Prussian Army.

https://en.wikipedia.org/wiki/William_Manley