@aria_elwen, thank you! That is interesting and useful! I remember watching a lot of shows contemporary with MLP as a kid but neither my mother nor I remember MLP airing. But I was 4 in 1986, and I only really got totally hooked on MLP from 1986-7 so may not have noticed. I was very attached to Red and Mokey fraggle prior to that

It's possible the specials aired but maybe MLP & Friends didn't.
The 1990s airing is the one I remember as well, that my sister's friend taped (as we didn't have cable) and then loaned us the tapes. That would've been in around 1995 I think. All of the episodes (unsure about Through the Door mind you) were aired in that airing, but I was really talking about the eighties on terrestrial TV, when I was a small pony-target-audience age kid (I was 13 in 1995). MLP Tales was also definitely aired in this slot as well so I am pretty sure we are remembering the same thing. But that's obviously much later and I think after most of the VHS were released.
As a kid I had 2 VHS, one I bought myself and the other I had really early so don't remember getting it but played it obsessively. That one was Ice Cream Wars/Revolt of PE and the other was Sweet Stuff and the Treasure Hunt/Would Be Dragonslayer. I never saw any other episodes until carbooting and the Sky 1 airing in the middle 1990s so I always wondered what happened with airing the series here.
MLP The Movie (as you say, the Film as it was marketed here) is advertised as being in cinemas in 1986-7 but I was scared of the cinema as a kid so I don't remember if it actually was in the local cinema to where I was living! I would think that would make its vhs release at earliest around 1987, so if it was on TV around that time I'm surprised I never saw it :/ My sister and I would take over the living room on a saturday and sunday morning from really early till around elevenish to watch kids tv so if MLP had been on we'd have seen it. UNLESS if it was on ITV, it aired regionally...which is not impossible.
Aside Through the Door I am certain there are UK PAL Vhs tapes for every episode and for some more than one with different combinations of episodes. Except maybe the MLP Tales. NOt sure how much VHS they got, and even DVD. I kn ow there's a full series US DVD and maybe an aussie one, but not sure there's been a UK one. Just a selection of episodes. (Can't remember if they're on the Girl Power DVD compilations but perhaps they are).