Wasn't charged anything for the install. Just £2.18 for delivery of the new router. Had the BT Openreach engineer round this morning at 8am and now have the following..
Wired connection: (using 200mbps Homeplug AV Powerline Ethernet adapters through the mains)
Wireless connection: (had to change the wireless channel from 'auto' to get better results)
Compared to my old 'non-fibre' download speed of approx 3MB, I am happy.
Excellent service from both Sky and BT. Sky keep you very well informed along the way. So far so good...