Last night I tried to watch my recording of the final I.T. Crowd, but it was unwatchable because of the interlacing. However, other programmes look OK. Whatever I put for video.output.vdpau_hd_deinterlace_method and video.output.vdpau_sd_deinterlace_method in ~/.xine/config_xineliboutput it gets replaced with "bob". The OSD doesn't have any options for VDPAU and none of the options it does have seem to make any difference.
I recorded it from the 4Seven channel because I forgot about the first showing on C4HD, and it seems only this channel is affected. Maybe they haven't set deinterlacing flags correctly? It does seem to be an issue of interlacing being disabled when it should be enabled, because my recording played correctly in mplayer with deinterlacing enabled.