Thanks Andi for the information (and I HAVE A QUESTION AT THE BOTTOM... please do read thanks)
Yes to all your questions. Unfortunately. However in the end I started a new template as for some reason despite trying everything no soloution worked.
THe ONLY way I've now managed to do this is by editing the soundset itself and creating individual sound sets for each player. So new violins are strings.violin.ensemble.dimension.1 -> strings.violin.ensemble.dimension.8 etc. Initially I added the number in this format violin.1. ensemble which did not work but eventually the added numeral at the end of the string seemed to solve things. Also it seems that even breathing on the mixer in Sibelius causes a nightmare of confusion. DON'T touch the (auto) soundset selection button!!! So my method which after a day of testing seems solid is:
1. Create a new soundset for each additional individual player (see above).
2. Save the soundset (in this case Strings).
3. Reopen Sibelius and then assign the various instruments in the score in the usual way.
4. N.B. Open the mixer. Play a short passage and if necessary reassign the individual staves to the CORRECT midi channel but DON'T touch auto... JUST the MIDI assignment.
This seems to work. However its very frustrating and the above was only arrived at after countless hours trawling the sibelius forum and reading some of Daniel's (who of course is now gone) responses.
I really think there should be a video tutorial for those seeking to solve the above. The current optimising sibelius for VSL pdf is good but doesn't help when one is trying to push things a little further I believe.
One final question Andi. Have the .fxp files changed recently. Some of my files (older string library matrixes) seem to have changed.
Thanks,
Juergen