My opinions are based mostly on my experiences on a forum for a British fantasy site (
Fantasy faction) and a few other places.
1. British fans seem to be more about epic fantasy overall and fonder of grimdark-style fantasy. Abercrombie, Lawrence, Bakker and other writers of this type seem to be big favorites there, though the articles on the site that hosts the forum do cover a range of authors and styles of fantasy. Grimdark seems to be nearly an "all boys'" club, from what I can tell. There are women who do write dark, gritty fantasy with a high body count and dystopian flare (Kameron Hurley comes to mind), but they don't seem to be included in the subgenre, even when books I wouldn't call Grimdark myself (like Wexler's books) are included on
such lists.
2. They seem to be more male-dominated than the US markets too. The FF membership is overwhelmingly male, for instance.
Other things that support this perception on my part is
this article, which suggests that male submissions greatly outnumber female ones at TorUK.
Also, the yearly Strange Horizons count for
2010,
2011,
2012,
2013,
2014 (which combines SF and F together) suggests that British SF/F is more male dominated than US, at least with regards to titles subbed to Locus. sadly, the total percentage of US SF/F books by women dropped in 2014. Hard to say if this was just a glitch, or a sign of a larger trend. Interestingly, in Australia, women seem to
hold a slight edge with fantasy in particular. No idea why different English-speaking countries would be different in this respect.
[edit]HA, just noted the date on the OP. Still an interesting topic. I think the new AWWC format, with its news feed makes it easier to get pulled into old and dead threads with recent replies, since I tend to skim it now and click directly on topics that look interesting, rather than accessing them through their forums the way I once did.