SKY+ DH boxes

[super__dan]

I currently have Sky with a relativly old SKY+ box(white).

I've keen to get a SKY+ HD box for the extra capacity and the free HD channels (not interested in paying another £10.25 a month). Can I just buy a box off the internet and aside from ringing SKY to get viewing card transfered, will it just work?

Tried to upgrade through SKY but fell out with them over how much they wanted.

Cheers