Hiya
In the end I used sub rip..
http://www.videohelp.com/tools/Subrip
It gives you the option of opening a VOB and extracting the subtitles as BMP... plus it lets you choose a relevant format, i.e Sonic DVD, Scenarist, Phillips VCD etc... Once ripped, you saved a text file as well and then it's just like importing them as new.
Plus, I used TMPGEnc to make the VOB files apppear as MPEG 2 files again.
I hope this helps.
Regards,
James