I use my own N66U router instead of the Sky Hub/Router connected to the Openreach modem, you simply need to obtain your user/pass and add this as a startup script to the N66U (very simple) so that it passes the MER over.
However, I believe most new customers get the new Hub which has the modem/router built in to one device so that might scupper your plans if you're a new customer.
If you get the new SR102 you will have to buy an openreach modem from somewhere (e.g. well known auction sites). Its still possible
