Best alternatives are:-
Use the RF output of your Sky+ box to connect to either a HDD/DVD recorder or a TV Tuner card in a PC.
I've successfully backed up many hours using the former option, but both will only capture in real time so it takes pigging ages if your drive is full.
What I did was connect my old Philips HDRW720 via standard Coax, recorded everything to the HDD, edited it to remove adverts etc.then dubbed it to a series of DVDs.
It took a while but now my 3 year old can watch In The Night Garden to his heart's content without filling up my Sky+ box.