Have a look at the
Digital Spy forum - sorry mods
There isn't a series link concept on Freeview though apparently they're working on it for the future.
I've got a Topfield TF5800 - a bit pricey, but fabulous bit of stuff - you can (easily) add replacement EPGs and so on and a lot of them will do a sort of series link based on programme names.
For example, I've got mine set to record anything called 'Planet Earth' and they just magically appear - it picks the timing up from the EPG that gets broadcast, so it won't get phased by schedule changes so long as the broadcaster updates the EPG.
The Humax PVR-9200T is supposed to be good too, though I don't know if it can do the sort-of-series-link bit - it'll obviously do 'every friday 9.00 - 10.00 on C4' though.
Do you want to transfer the recordings to your PC? If so, it's the Topfield or the Humax or as far as I know nothing else.
If you can live without that & the series link then there are cheaper ones too - the new Daewoo DSD-9502T seems quite good.