Runnermum,
Blackmores recommend 2 of their pregnancy vitamins daily. I believe that recently the RDI of folate for breastfeeding and pregnant women in Australia was increased to 500mcgs. Previously it was 400mcgs. I am not sure if the 500mcgs RDI has been released but I know that it will be very soon if it hasn't already been.

In Europe the RDI of folate for pregnant and breastfeeding women is 800mcgs. Many women who see a FS are on much higher doses.
For example I am on 5mgs due to recurrent miscarriage.