what for?
You have sky plus hd iirc?
I realise your hd box unfortunately wont allow you to tune to itv hd but you are missing absolutely nothing there, trust me. The Bill and champions league.(in sd anyway)
So you dont need the freeview tuners either imho.
I have an older dvd recorder bought prior to sky plus arriving under my tv some years ago, with the intention of recording the best stuff from sky. Havent ever used it apart from making sure it works. Just dont need it. Sky plus is so easy to use, and recording from it means you cant watch anything else anyway, until the recording is finished.
(Er, must check that, havent used it for so long they may have improved it on the software upgrades.)
My recorder is nothing more than an expensive clock, and a crap one at that as the digits are too small.
And Kevins comments re menus are true here as well.
And another thing, (well maybe?), have they made a recorder that will record and playback in hd with 5.1? I am very out of touch with the tech, last i looked, along time ago now, one did not exist...

Afaict, you may be better off finding a fault with your current hd box, changing it under warranty for the one that allows the new epg and itv hd, then sticking a bigger hard drive in that...?
Or am i out of touch?