Just been rung up by SKY offering HD+ box, standard installation both for free, and £10/month for the HD pack.
This is instead of the previous £60 install deal for existing customers. Other than ESPN half price deals through the post this is the first proper deal I've been offered, don't even have SKY+!
I accepted, of course! Details on my account accessed through the SKY box show all charges and credit charges as existing customer deal.
I am hopeful others may be able to benefit hence I am posting.
SKY customer services is 08442 414141, always worth asking.