Paul, we had a similar problem. It appears that our upstream regional
provider had not allowed us to be fully authoritative. For example, reverse
lookups were only authoritative for them on many of the blocks of addresses.
It caused a defininte problem for us.
I contacted them, explained the problem and they were able to correct it in
a day.
You need to contact your upstream provider abou this. DNS transfers are
usually complete in a day of them notifying you.
David Payer
OMNI Internet
www.ia-omni.com