Hi Ian
I tried swapping the 75 resistor on Scart pin 16 for a 220, but it didn't make any difference at all. I'll try swapping the 330 on Scart 10 for a 270 as that's the other value that is different between your diagram and Alexh's suggestion in this post:
http://eab.abime.net/showpost.php?p=572128&postcount=18
I'll let you know how it goes.
Rocs9005.