Success here - I'm an expat using a slow VPN connection. I used the trial version of GetFLV 8.8.46.

I downloaded 10 MB (trial limit) of Derren Brown and then extracted the .264 with FLV extract.

I used WinFF to extract the ACC and convert to AC3 then muxed the H264 & AC3 streams into a MKV container using MeGUI to play on my XBOX running XBMC. (Xbox is not fast enough to decode AAC) - it plays fine.

PS - I also tried the as-downloaded .FLV file on the xbox using the built in DVD player and it appears it would play at the right speed if it didn't struggle with the AAC codec - so are there PC based players that would play the FLV stream at the correct speed without the demuxing/muxing...?