I remember seeing lots of movies at the video store based on Anderson shows. Were these new films?

Most likely not. There have been numerous compilation films released that have combined episodes of Gerry Anderson shows. These compilation films were produced by ITC with the assistance of STARLOG's David Hirsh around 1980 in response to demands from cable networks for "family" programming to compete with the Disney Channel and other similar services which were then becoming available for the first time. The package was dubbed "Super Space Theater", and the compilation films released were:

CAPTAIN SCARLET VS. THE MYSTERONS

CAPTAIN SCARLET AND THE MYSTERONS episodes "The Mysterons", "Winged Assassin", "Seek And Destroy", "Attack On Cloudbase"

REVENGE OF THE MYSTERONS FROM MARS

CAPTAIN SCARLET AND THE MYSTERONS episodes "Shadow Of Fear", "Lunarville 7", "Crater 101", "Dangerous Rendezvous"

THE AMAZING ADVENTURES OF JOE 90

JOE 90 episodes "Most Special Agent", "Splashdown", "Attack Of The Tiger", "Arctic Adventure"

ALIEN ATTACK

SPACE:1999 episodes "Breakaway", "War Games"

COSMIC PRINCESS

SPACE:1999 episodes "The Metamorph", "Space Warp"

DESTINATION MOONBASE ALPHA

SPACE:1999 two-part episode "Bringers Of Wonder"

JOURNEY THROUGH THE BLACK SUN

SPACE:1999 episodes "Collision Course", "The Black Sun"

THE INCREDIBLE VOYAGE OF STINGRAY

STINGRAY episodes "Stingray Is Launched", "Plant Of Doom", "Countdown," "The Master Plan"

INVADERS FROM THE DEEP

STINGRAY episodes "Hostages From The Deep", "Deep Heat", "The Big Gun", "Emergency Marineville"

THUNDERBIRDS COUNTDOWN TO DISASTER

THUNDERBIRDS episodes "Terror In New York City", "Atlantic Inferno"

THUNDERBIRDS IN OUTER SPACE

THUNDERBIRDS episodes "Sunprobe", "Ricochet"

THUNDERBIRDS TO THE RESCUE

THUNDERBIRDS episodes "Trapped In The Sky", "Operation Crash Dive"

INVASION:UFO

UFO episodes "Identified", "Computer Affair", "Reflections In The Water", "The Man Who Came Back", "ESP"

The DICK SPANNER P.I. videos that are available are also compilations of the shorts done for NETWORK SEVEN. Ironically, in the U.S., the compilation movies have seen wider TV screenings than the series they are based on in many cases, particularly in the case of INVASION:UFO, the compilation film based on the seldom-screened series UFO. In many cases, the fact that footage from certain episodes was used for this product line prevented distribution of those individual episodes on videocassette and/or laserdisc due to British copyright laws; the SPACE:1999 two-part episode "The Bringers Of Wonder" is not available on the commercially-produced laserdisc set for this reason.

However, there are two films based on THUNDERBIRDS that are not merely compilations of series episodes, 1966's THUNDERBIRDS ARE GO and 1968's THUNDERBIRD 6. Each were unique productions done for the cinema by the newly-formed Century 21 Productions, though neither had the success of their TV series counterpart. Both movies occasionally turn up in Sunday afternoon and late-late-show slots.