Windows 7 network profile detected as public not domain

Hi,

I have a starnge issue....newly built Windows 7 pro PC's network profile is detetced as domain profile when first joined to domain but after reboot swtiches to public profile. This happens with both physical and virtual windows 7 OS's
I have tested usual two checks
1. dns suffix for this connection matches reg key “HKEY_Local_Machine\Software\Microsoft\Windows\CurrentVersion\Group Policy\History\NetworkName”
2. the client is able to connect to our dns server. (telnet to port 389)

when I check into "manage or delete network locations" the domain profile is listed and type is managed but is not in use.
If i delete this profile and remove and readd the workstation to the domain the connection is given the a domain location profile but again losses it on reboot.

>our clients are DHCP
>we have our dns servers on one vlan and workstations on different vlans...( but have tried putting on a win 7 on server vlan too)
>our router which provides the gateway mac is vrrp(hsrp) but havent had a failover so mac for each vlan gateway is consistent but differnet to each other.
>we have windows 2008 r2 active directory domain

these are the first windows 7 images we are about to deploy in our network and have a deadline but wouldnt like to start of on wrong foot.

any ideas please??