Plug DVD recorder output scart into scart 1 on back of TV
Plug switching unit1 into scart 2 on back on tv, and plug one scart from the sat box and freeview into the switching unit1
Plug switching unit2 into dvd recorder input scart, and plug one scart from sat box and freeview into switching unit2
messy :( and requires each device to have 2 scart socket, and you have to switch.
Maybe someone else has a more practical solution.