Big Finish, Fourth Doctor Series
I don't recall the Vardan's as villains in Dr. Who but obviously, their abilities are quite easily used on Earth, where radio waves, communication cables, and satellites would allow them to transmit themselves around the globe quickly. So the idea that they would invade Earth is easy to understand. But why don't they do it more often than the Daleks or Cybermen? Not for me to say. Much as water-based life forms would like Earth, so would waveform-based life forms at this time in our history.
The Doctor and Romana are hanging out, waiting for K-9 to return from taking the TARDIS around the cosmos to lay false trails for the Black Guardian. Then he gets shut down by a wave that is being tested out on Earth. The Doctor and Romana investigate to find a scientist knocked out being investigated by Miller, a military man obsessed with filling out forms. They find the scientists' daughter in the next room and so the team splits up, investigating the mentioned invasion in the scientist's journal.
So the investigation leads the Doctor to Vardans and Derek, one of the vanguard Vardans. And the plan to open up a channel to the fleet to invade Earth. This story is a fun romp! And seagulls even help save the world in the end. The Doctor and Romana defeat them, of course, with the help of a couple of humans with ingenuity. That should be a semi-companion title "Human with Ingenuity" - of course that doesn't guarantee survival... But it sure was a fun story!
Tom Baker (The Doctor), Lalla Ward (Romana), John Leeson (K9), Karl Theobald (Mark Lanchaster), Phil Mulryne (Barnaby Miller), Alix Wilton Regan (Jill), John Banks (Derek Fretus)
Writer: Justin Richards
Director: Nicholas Briggs
Release: January 2016