£100 for a cable? I thought that was hideous until I looked here in the U.S. Then I actually looked for the 'best buy' I could make on a cable--$1090!
So, methinks those cheap £100 must be absolute crap. They probably don't have techno-babble features like "Critical Stable Geometry for high-quality audio and video signal transfer" or "solid long-grain copper for a strong signal."
The last thing you need is for your short-grained copper cable's critical geometry to go all unstable.