We start this time with the Pump room set seen in The Macra Terror episode 3, broadcast 25th March 1967.
Their last known appearance in season four is in the first three episodes of The Faceless Ones, , broadcast 8th-22nd April 1967.
The panels don't feature in the last story of season four, Evil of the Daleks, which means they've appeared in 4 season 4 stories.
They're also not in the first story of Season 5, Tomb of the Cybermen, but they make regular appearances for the rest of that season.
The Abominable Snowmen episode 1, shown on 30th September 1967, is notable for being their first appearance inside the Tardis:
In The Enemy of the World 4, broadcast 13th January 1968, they can be seen inside Salamander's underground base:
No telesnaps for this episode existed so this appearance was hidden till the episode was returned in 2013.
The same panel that is seen in Salamander's underground office makes a blink and you'll miss it appearance in The Web of Fear episode 1, shown on 3rd February 1968,
The Fury from the Deep, broadcast from 16th March to 20th April 1968, makes extensive use of the panels in the main control room set:
Thanks to some colour film shot at Ealing Studios we can see this set, and the panels within again, in colour.
The panels are used elsewhere in the refinery complex.
More are featured in the gas rig control room set and for the first time these include black panels. Are these the originals painted or different ones?
A couple of panels make a fleeting appearance in the Tardis at the end of Wheel in Space episode 6, the last episode of this season, shown on 1st June 1968:
During Doctor Who's fifth season they appear in 4 out of the 6 stories.
In season six another panel is visible in the Tardis during The Mind Robber episode 1, broadcast 14 September 1968.
Their next appearance isn't in Doctor Who but the Out of the Unknown, episode This Body Is Mine shown on 21st January 1969. Many Out of the Unknown episodes in Series 2 & 3 don't survive so there may well be other appearances which we can't see. Fortunately this one does and you can watch this episode, directed by long time Doctor Who director Douglas Camfield on the Out of the Unknown DVD Set!
They return in the Doctor Who story The Seeds of Death and are most prominent in episodes 4 & 5 which were broadcast on the 15th & 22nd February 1969.
Noticeably the panels, which are mounted on wheeled units, swap places between the episodes!
After that appearance in Patrick Troughton's third and last season they seemingly disappear until the second season of Jon Pertwee's Doctor when they appear in the colonist's dome in Colony in Space broadcast from 10th April - 15th May 1971.
This is their last known Doctor Who appearance but the last time they're seen is in this publicity photo showing the Lab set from the third season of Doomwatch, which began broadcast in June 1972.
I have The Doomwatch DVD but haven't managed to spot any in the three existing third season episodes. That, so far, is it. If you know of any other appearances of these panels then I'd love to hear from you, especially if you can provide screen captures. Comment bellow or Tweet me @philip_ayres.
My thanks to the good people of Roobarbs Forum for finding many of these appearances and drawing my attention to them!