I love Dashiell and Hugo! I think Dashiell Hugo would be so handsome! I think both Dashiell and Hugo would be quirky, fun, smart. :). I would love to meet a Hugo or Dash. :)
I absolutely LOVE Hugo... I guess I pretty much agree with everyone else. Hugo and Dashiell are great and Burl is strange. That's how I was told Beryl is pronounced. I always thought that Beryl was feminine and strange in general... :/ I went to school with a guy whose last name was Bixby, so I really can't see it as a first name. Fielding is kind of cool too. It's not something you hear all the time.
You'd like an "unusual, artistic, British, countryside, strong, intelligent" name? OK... breaking down your favorites...
Hugo: this is in no way a British name. It's given in Britain, sure, in the same way that Jaden and Enzo are given-- as a cultural import. The British form is the Norman Hugh, or the Welsh Huw as pointed out above. It does not read "pastoral" or countryside to me. And it certainly is not suffering from over-popularity; the majority of US Hugos are Hispanic and the name has been quietly given in the community for decades. Hipsters are starting to catch on to it. In 2011, exactly 202 little boys were named Hugo, spread out over >1 million births. So, if this is your favorite name, a name you've loved for years, by all means bestow it.
Fielding: this hits all of your marks. "Field" evokes the countryside, it's a British surname, it strikes me as a rather patrician and/or literary name, and it's unusual without being odd. 8 boys were named Fielding last year.
Burl this actually misses all of your marks. It suffers from the terribly unfashionable -url ending; it skews more huckster rube than fine country gentleman; and I could never imagine anyone in the UK carrying it.
Bixby: I like the quirky style of Bixby. It's a British surname but decidedly nonpretentious, and it reminds me of Bix Beiderbecke and therefore always carries a nice jazzy association. I think this one should stay under consideration.
Dashiell: if you don't want trendy, stay away from Dashiell. This is the hipster name par excellence. My baby is in daycare with two of them. The SSA data does not reflect it, but if you live in Brooklyn, SF, Santa Monica, Austin, Seattle, Portland or other hipster pockets you will run into other little Dashes.
Lytton (as in Strachey)
Somerset (as in Maugham-- and a County in England)
Auberon (as in Waugh, and King of the Fairies in British folklore)
Stirling (as in Castle/Scotland)
Strathmore (as in the ancient earls of Strathmore)
Linley (as in Viscount Linley)
Senneck (the medieval abbreviation of Sevenoaks, Kent)
Copley (John Singleton Copley, American painter; derived from a copse of woods)
I love Hugo the most!
I'm not sure of the exact popularity of Hugo where you are, but I don't think its booming anyway.
My middle name (Lucy) was the name of a cat my mum had before I was born. She loved the name so much that she gave it to me :) I don't mind being partly named after a cat!
My second favourite from your list is Dashiell. I'm a bit of a nut for typography/fonts and I love the way this looks written down. I like the option of "Dash" for a nickname too.
My least favourite is Burl, which I've never seen before. It reminds me of "burly" which could be a potential nickname, which could be unfortunate if he's not burly.
I love Hugo!