Playback of WTV files does not display DVB subtitles
Although VLC's "Video | Subtitles Track" displays an option "Track 1 - English" for a WTV file which contains a DVB subtitle stream, ticking that option does not cause the subtitles to be displayed.
In contrast, a TS file generated from the WTV file (eg open WTV in VideoRedo, save as TS) does display the subtitles in VLC when "Track 1 - English" is ticked.
Note that this is for DVB subtitles embedded in the WTV file, rather than a separate SRT subtitles file.
This behaviour has been confirmed with a variety of off-air standard def PAL (704x576x25) WTV files recorded by Windows Media Centre, though a thread on VideoLAN Forums http://forum.videolan.org/viewtopic.php?f=14&t=103864 shows that it has also been seen for NTSC WTV files as well.