Should this not be Dave (Slitheen), or perhaps Dave (Raxacoricofallapatorian)? I see no need for a conjectural title.
Talk about it here.
A member of the Slitheen family disguised himself as the human, Dave, using Dave's skin as a skin suit. In 2009, another Slitheen stole a matter compressor from the Pharos Institute and was chased by Sarah Jane Smith and her Gang. He managed to escape and met with Dave Slitheen. They planned to use the matter compressor to turn Earth's atmosphere into a giant diamond. After Sarah Jane failed to stop them, the Blathereen arrived and executed Dave and his associate. (TV: The Gift)