I have a Pansonic DMR BW 720 which has a 1TB hard drive and records two channels at the same time and can burn to DVDs or Bluerays and is also a 3D blueray player as wel. I tend to find that BBC HD films are usually the only ones that transmit in 5.1. ITVHD and C4 HD usually only transmit in stereo even if the Picture is in HD. I have several Pansonic DVD recorders they are always reliable and are easy to use as well. I find that my Onkyo recever will convert a stereo recording to 5.1.
I jope this helps.