Have had the same problem for six months. Dyson themselves will only allow trained service staff to have the "open sesame" to the area you need to access. At £50+ for the call out, it seems a very expensive way to replace, or trim and refix a power lead. I have done the more dangerous trim and twist and insulate with tape close to the cable outlet, but it gets in the way of emptying detachment and power button.
John E from Devon, October 2010