What would a BBC version of The Magician’s Nephew look like?  The Victorian time setting would probably be used. I can picture it resembling the Dickens series of the 1970’s and ‘80’s, which was shown here in America on PBS’ Masterpiece Theatre. In some ways the other Narnia miniseries did look about as old fashioned even though the part of the story that takes place in our world was at a later time.  The BBC series looked vintage even though it was made in modern times. But that was much like C. S. Lewis intended it to be.  And that is the closest to the spirit of the original books.

Posted by: @narnian78

What would a BBC version of The Magician’s Nephew look like?

If you mean a BBC version as in a continuation of the late 1980s / early '90s series — made in the same era and on the same shoestring budget — well, I would guess the technical difficulties (virtual impossibilities) of it must have had something to do with why they chose not to even try to adapt that story. There was simply no way that they could have portrayed Fledge as a convincing flying horse, for a start. Not to mention the creation of Narnia itself, which would (probably will) be a stretch even with today's technology. Back then, to portray what Lewis described in the book — well, CGI was still in its infancy in the early 1990s, and it cost a bomb (so to speak) to produce anything lengthy and complex with it. The BBC experimented with a few CGI animated characters in their version of LWW, and the results were so awkward-looking and unconvincing that they didn't try that again in any of their other Narnia adaptations.

And using CGI to animate the mouths of real animals, so that they look like they are talking, didn't come along till 1995, in the film Babe. That would be needed in order to have Strawberry / Fledge played by a real horse, which is essential to the plot (because he starts out in life as an ordinary London cab horse, not as a Talking Beast). Never mind having him grow wings and fly, as I mentioned above!!

On the other hand, if the BBC decided to do new adaptations of the Narnia books today, then they would have the technology (and, I hope, enough money) to do a much more sophisticated job. But while nearly all their adaptations of classic children's stories 30-35 years ago were almost painfully faithful to the books, I don't know if they would be if they started making new adaptations today. I suspect there'd be a lot of concern about making them relevant to a modern audience and removing or changing anything that wasn't in line with (their perception of) "today's values". And the results might very well be even further removed from the original stories than Greta Gerwig's, so far, looks like being.