HN is viable because it has a worldwide community of hackers, good moderation and someone writing $120K checks. If the only thing technews.london does is reduce the scope then I fear it won't live long, like so many HN clones before it. I only recall two that were successful and they were successful by doing something HN did not (general business news and designer focused news). London is already on HN as it is.
Cool!<p>Also didn't know there was a ".london" TLD, but I'm not following such things very closely. It seems anything is a TLD these days.<p>Clicking on a story's link opens a new tab. This site doesn't work like that, which is very confusing since it breaks the pattern and creates confusion.<p>Probably only matters if you think your users are going to be readers of both sites, but that does seem rather likely to me, at least.
I'd rather smaller lines for each story. I can scroll in and out if I want it bigger. I'd also like to see a different font used. I don't like the logo placement as its distracting and in the way.