Hi Dominic,
Please update Acrobat to v11.0.09 and check if you still observe the issue.
In the print dialog box, go to 'Advanced'> Under 'PostScript Options' select 'Send at Start' and then try printing and check.
Which drivers are you using- is it PS or PCL?
What happens if in the print dialog box you select 'Print as image' option and print?
Regards,
Ravi