They were scavenging from the hulk of a time ship. His efforts to drive them off only resulted in their attacking him. Although he retreated to France on 5 October 1930, materialising his TARDIS on board the British airship R101, he inadvertently towed one Vortisaur, namely Ramsay. The Doctor found this out when it began to attack the airship crew.
The Doctor and his new companion, Charley Pollard, rode the Vortisaur to escape the crash of the airship. Charley took a liking to it and named it "Ramsay" after the Prime Minister of her time, Ramsay MacDonald. (AUDIO: Storm Warning)