Professor Kirke's House

The filming location for Professor Kirke's house in the BBC version of "The Lion, the Witch and the Wardrobe" (IMDb) is Llanvihangel Court.  Some of the rooms, especially the spare room that contains the wardrobe, look like they might be sets, but everything else appears to be filmed there.  For evidence, watch this YouTube copy of "The Lion, the Witch and the Wardrobe", specifically at these times, noting:

• 3:16 - the front of the house,
• 23:10 - the fountain,
• 48:31 - the garden house (guardhouse) next to a red tree and
• 49:01 - the stained-glass window,

and compare them to these 2017 photographs of Llanvihangel Court and the photo of the stained-glass window here: Elizabeth I from Elizabeth I and the Family of Charles I - work from Stained Glass in Wales (llgc.org.uk)

Unlike some other locations for the series, the house wasn't mentioned in closing credits.  At the time of filming, it was a private house and the owners may have not wanted publicity.  In recent years, the house appears to have hosted tours and events.  It has a web site: https://www.llanvihangelcourt.com/

I found the house by looking for recognizable objects in scenes set inside and outside the house and searching the Internet for them.  It took me a while to notice the stained-glass window, but eventually I did, and that was the key.  It depicts a lady that looks like Queen Elizabeth I.  On closer inspection, I saw that there is a gentleman on either side of the lady and one of them is laying down a cloak.  I recalled there was an incident where Sir Walter Raleigh laid down his cloak for Queen Elizabeth so she would not have to step in a puddle.  Googling "elizabeth", "cloak", "raleigh", and "stained glass" as required terms turned up the "Stained Glass in Wales" web page mentioned above, which identifies the location of the stained-glass window: Llanvihangel Court. 

As for the puddle incident, Wikipedia says it is probably apocryphal.  Another source flatly states that it never happened because the first known written reference to it was written 80 years later by a Thomas Fuller, who sometimes fabricated stories.  Of course, it is a non sequitur to go from "this person sometimes fabricates stories" and "this person was the first person we know of to write about it" to "we know this never happened", so I disagree.  You can read Thomas Fuller' account of the incident here.  Actually, it isn't so much an account as a mention.  Quoting Fuller: "his introduction into court is said to have born an elder date, from the time he spread his plush cloak for Her Majesty to step upon over a wet place".  It seems like Fuller is stating hearsay or repeating tradition.  As it is written, I don't know why he would have made it up himself.  For myself, I would rate the incident to be about as likely to be true as any bit of remembered information about a historical person, or any other unproven statement made in the book it was included in.