Hi Mark,
I asked this same question a few years ago by creating this thread:
http://www.iceinspace.com.au/forum/s...d.php?t=134288
My own outcome:
Dulux Terrace White (Colour card number 9W) is a very similar shade to 'Skywatcher HEQ5pro' white. Not perfect -but very, very close.
Regards, Dean