Currently 7 videos exist, all of Marillion. Here's the listing:

Title : Recital of the Script
Time  : 55:00

        Script for a Jester's Tear / Garden Party / Chelsea Monday /
        He Know You Know / Forgotten Sons / Market Square Heroes

        Very good live video from a concert at the Hammersmith Odeon. It
        says on the back:

       "It was the night a dream came through - when two years of motorway
        madness, greasy spoon meals, and interminable club gigs suddenly
        all seemed worthwhile. Hammersmith Odeon - the oft-sought but
        seldom attained aim of every rock band. A capacity audience
        hanging on to every note and a massive stage for Marillion to
        present their stunning visual theatrics in spectacular style.
        Powerful, dramatic music; provocative lyrics and superlative
        musicianship.  A night to remember - for Marillion to savour with
        understandable relish as a major milestone in their career"

Title : Grendel/The Web (EP)
Time  : 29:00

        Contains: Grendel/The Web (live)

        This video has two live tracks; both were encores at the Hammersmith
        Odeon concert of "Recital of the Script". It says on the back:

       "'Grendel' was originally released on vinyl in October 1982 - our
        first ever release on EMI - and an unplanned third encore at the
        Hammersmith Odeon show in April 1983. 'The Web' has not been per-
        formed live since this show....."

Title : 1982-86 The Videos
Time  : 35:00

        Market Square Heroes/He Knows You Know/Garden Party/Assassing/
        Kayleigh/Lavender/Heart of Lothian/Lady Nina

        All the videoclips up to 1986. Some are very good, especially Garden
        Party is very funny.

Title : Incommunicado C/W Sugar Mice
Time  : 8:46

        Contains: Incommunicado/Sugar Mice (videoclips)

Title : Live from Loreley
Time  : 87:00

        Slainte Mhath / Assassing / Script for a Jester's Tear / Incubus / Sugar Mice
        Hotel Hobbies / Warm Wet Circles / That Time of the Night / Kayleigh / 
        Lavender / Heart of Lothian / The Last Straw / Incommunicado

        Good live video, recorded in St. Goarshausen (Germany) on July 18,
        1987. It starts with "La Gazza Ladra" as intro and some backstage
        shots.

Title : From Stoke Row to Ipanema
Time  : 90:00

        Hooks in You/Uninvited Guest (videoclips)
        Eric (live rehearsal)

        Hollywood Rock Festival, Brazil 1990
        Kayleigh/Lavender/Hooks in You (live)

        Easter (video)
        The Ultimate Gift (live rehearsal)

        De Montfort Hall, Leicester, England, 24th April 1990
        The King of Sunset Town/Easter/Holloway Girl/
        Berlin/Season's End (live)

        This video contains some interview with the band, especially to
        introduce Steve Hogarth, who recently joined the band at this time.

Title : A Singles Collection
Time  : 52:00

        Sympathy / Cover My Eyes / No One Can / Dry Land / Hooks in You / 
        Uninvited Guest / Easter (with Hogarth)
        Warm Wet Circles / Incommunicado / Kayleigh / Lavender / Assassing / 
        Garden Party (with Fish)

        Once again a lot of videos, only the first 4 tracks were not released
        on a video before. Accompanies the CD with the same name. In the
        USA this video is called "Six of One, Half a Dozen of the Other"

Title   : Kerrang! Metal Monsters
Catalog : R0471VH

        This is a Kerrang! compilation tape (or video LP actually) that has
        various video's, including He Knows You Know. Full tracklisting:
 
        Iron Maiden - "Aces High"
        Whitesnake - "Slow An' Easy",
        Helix "Gimme Gimme Good Lovin'"
        Wendy O. Williams "It's My Life"
        MARILLION "He Knows You Know"
        Motorhead "Killed By Death"
        Scorpions "Rock You Like A Hurricane"
        W.A.S.P. "Love Machine"
        Queensryche "Queen Of The Reich"
        Armored Saint "Can U Deliver"
        Alcatrazz "God Blessed Video"
        Bon Jovi "Runaway"
        Kiss "Heaven's On Fire"