Thanks for that input.
The DR test was really to check the integrity of the active directory restore, as we have 5 active directory servers which I restored, there was no replication working, apparently this is due to USN rollback
in short I needed to go back to one domain controller (the one with the FSMO roles) and then force removal and perform a meta data cleanup of the other DCs, then once this was performed I could then repromote the other DCs back and then replication began working.
apparently to prevent this issue I do need to use a AD aware backup, its a shame the Netapp out of the box there is no offering but will certainly look at Commvault.
The good news is if your using Windows 2012, this is no longer an issue and you can restore virtual AD servers without issue....