Cycling at the Speed Limit: Take the Lane?

[HLaB]

There's a road near me which is a 30 mph zone, is downhill and bends to the left. I can easily hit 30mph down there and always take the lane as its often unsafe for cars to overtake, this doesn't stop most of them though

If the road was wider or was straighter I would keep more to the left, no point annoying people unnecessarily. As others have said it depends.

It was a unrestricted zone but I couldn't believe some idiot overtook me here the other day; I suppose it was better overtaking me here when I was still going 22mph, rather than 2 secs later when I was going 35mph