NTL Langley Di4001 boxes with hardware type 0 and 1 have an S-video output but no RGB.
http://www.cableforum.co.uk/board/sh...ad.php?t=16344
BTW, S-VHS is a tape format and nothing to do with a video signal or connector.
For some converters try
http://www.keene.co.uk/ and in particular:
http://www.keene.co.uk/cgi-bin/searchxx.pl?13con,13OTH