Leon Perkins

Perkins was a scientist.

He and Dr Schulz travelled in time using a vortex manipulator.

Together they were tasked with procuring a painting from 1899. By mistake they travelled to 1999 and took a painting from a small museum, bringing it back to their client in exchange for a shot for Dr Schulz.

In 3912, the Thirteenth Doctor, Yasmin Khan, Graham O'Brien and Ryan Sinclair saw his hand sticking out from a portal because his vortex manipulator was malfunctioning. The Doctor calculated the space-time coordinates he will pop out next and there Ryan and Yasmin pulled him out. (COMIC: A New Beginning)