I'm back in my hotel room tonight so have just tried a couple of things.
If I try and stream standard definition content over the internet - it mostly works (although if the bitrate of the recording ever tops out at 3meg then the upstream on my home broadband will be saturated and the program will stutter or buffer).
If I try and play high definition content over the internet, it doesn't play well at all (pixellation and it plays almost slow motion) so this is clearly exceeding the upstream bandwidth available on my connection and possibly the downstream of the hotel wifi.
There's so many variables it's hard to pin down which might be failing you but worth checking if it's SD, HD or both that gives you trouble and also checking you aren't exceeding your upload bandwidth of the connection hosting TVHeadend.