Hi al,
It's an external hard drive you'd be after, rather than a Freesat box.
Buffalo JustStore hard drives are compatible with the V20 (£50 for a 1tb version).
You connect this to one of your V20's USB ports and your TV becomes a single tuner PVR (you can then pause, rewind and record TV).
It's a great investment, in my opinion. You'd have twice the recording capacity of the most expensive Humax Freesat PVR; and it's dinky, too, so could sit easily out of sight.
If I buy a V20, I'll immediately invest and begin building a collection of HD recorded content!
Hope that helps...