I understand why the Telmarines had non-British accents in PC, but we know they were a mixture of accents Spain, Italy, Portugal etc. Perhaps to people from those countries the mix seemed odd.
I would want anyone playing an English character to give a convincing and appropriate accent for the character (including their social class and part of Britain). Caspian needs to stay upper class English (posh) and the Narnians should have a suitable mix of accents. The Earthmen and the Giants - all sorts of possibilities, but there's a need to be wise about not making them sound like any particular nationality - as they are the baddies!

Generally I prefer British accents, simply because I like the British accent. But I don't think that all the characters must needs have them. I do think that the main characters should have a British accents (either be British themselves, or be able to put on a good fake one) but for extras and minor characters, I wouldn't mind having other accents as well. Also, 'British accent' can have a very divers meaning. There are lots of different types of British accents. I always thought of the dwarves having a more rough northern type of accent, and for some reason I always thought of the giants as having a cockney accent, not quite sure why though From the first time I read the Chronicles of Narnia, I was sure that all the giants had a cockney accent.

I said 'yes' to them all having British accents. They can have a variety based on geographical location and role, but anything non-British for "The Silver Chair" just doesn't make sense!

It is very important to me that all of the children from our world have English accents. After that, all I want is consistency.
I really liked the idea of the Telmarines in PC being Mediterranean, but their accents were all over the board and it drove me nuts.

As long as Jill and Eustace have British accents it's fine and all good. As for other characters I like to hear some variety of accents.

I think they should only use non-British accents if it serves a purpose.

I liked the use of Mediterranean accents for the Telmarines because it hinted at their swarthy pirate ancestry. I even liked the somewhat American accent of Michael Madsen for Maugrim in LWW as it gave him a kind of 'American Gangster' type persona which I think complimented his character well.

The films How to Train Your Dragon and 300 both used Scottish accents well to give the audience a sense of the aggressive tribal cultures it was depicting (Vikings and Spartans respectively) by providing an accent that anyone who has seen Braveheart can relate to as being similarly tough and fearsome. Though the use of Irish accents for similar reasons in Oliver Stone's Alexander movie (it was supposed to indicate how the Macedonians were to the Greeks as the Irish are to the English) just came across as utterly ridiculous.

So to cut a long story short, as long as they have a valid artistic reason for using a particular accent, I think that is fine. Though the last thing you would want is to have characters popping up with entirely random modern day accents which don't fit the quasi-medieval fantasy world setting.

I had no problem with the Telmarines' Mediterranean accents because they fit the story in PC and their characters. SC is different. I see the foreign parts, beyond Narnia, like Scotland or something. There's no room for the Mediterranean here, not even Scandinavia or Russia. I would allow the latter for the non-Narnia (non-English) characters only in desperation.

Oh pleeaase! Not the Scottish accent! That one is barely understandable in real life! I should know. All those "yon's", "bonnie wee bairns" etc! It gets very tiresome to have to have a dictionary to translate every thing that is said even ordinary sorts of expressions from 'pass the bread' to 'that stag told me he was tough'. No wonder Puddleglum thought he was a 'Respectobiggle"!

I agree that King Caspian and even Prince Rilian would have at least a slightly "posh" accent, but what is wrong with a Universal English accent for everyone else? LOTGK could have a vaguely Northern Irish/Scottish/American accent. We are told in the book that LOTGK could "roll her R's" delightfully, which is something I am continually told native born Australians can't do.

I hope that the actor/actors who play earthmen such as the Warden of the Marches or Mullugutherum have that flat, hoarse "black" sort of voice that was done so effectively in the Family Radio Theatre version of Silver Chair. It was done far more effectively than was the BBC audio drama production.

People can fake British accents pretty well sometimes, but I find that I can often easily tell when someone is faking their accent. It makes me cringe when I hear a bad accent, so I'd rather hear the real thing. There's nothing worse than hearing an actor switch between dialects!

Faking a British accent has more than one level - it may be easy to fake the accent to someone from another country, but to fool someone from UK (particularly who is from the part of UK that the accent is supposed to be) it will be much harder.
I know Americans often think they can fake a British accent, but usually they don't know what accent it needs to be.

In my own country - New Zealanders are often poor at faking an English accent, and I have cringed at amateur actors putting on a broad Yorkshire accent for a character in London!

If the children from our world don't talk British (which isn't just about the accent, but also using British forms of speech), then it's a deviation from the book which I find distracting and annoying. I was annoyed by the Americanisms in the dialogue of the Harry Potter films, even though the accents were still British ("bathroom" for "toilets" etc.)

For me as long as the children from our world have British accents I'm good they are British in the books and I don't see any reason to change that.

If the children from our world don't talk British (which isn't just about the accent, but also using British forms of speech), then it's a deviation from the book which I find distracting and annoying. I was annoyed by the Americanisms in the dialogue of the Harry Potter films, even though the accents were still British ("bathroom" for "toilets" etc.)

However, in the last film, where Harry, Ron & Hermione reach the Room of Requirement, finding in it a girls' "bathroom", did they also include book Lavender Brown's remark that the girls would quite like to wash?

I didn't notice any Americanisms in either the HP films or the Narnia films, to be honest. But then, would anyone really notice what is Australian or New Zealand usage unless it was really overdone? Contrary to USA usage, we do have bathrooms but only if they contain baths and/or showers.

I thought that the "bathroom" they were talking about was actually the dormitory bathroom - containing baths, showers, washbasins, and toilets. I have seen the second HP film and I believe that is what I saw in that scene.