MS AD / SYSVOL Replication errors and SYSVOL Policies not replicating

We have an issue on a domain where we introduced a server 2012 R2 DC and the SYSVOL Policies are not replicating.

I've been tearing my hair out on this issue all day and can't solve it.

I have run FRS Diag and there are errors. Can someone please help?

KT-DC1 (original DC): Server 2008 R2 Standard

JFI-DC1 (new additional DC): Server 2012 R2 Standard.

I can supply more detail / errors, but the errors include:

KT-DC (original DC):

NTDS Replication 1/09/2014 5:01:34 a.m. Error 2513 Attempting to set the desired authentication protocol for a connection to the following DSA failed. DSA: 79483465-b61c-4fa9-9ded-d8115504707a._msdcs.kitchenthings.local Additional Data: Error: 1747 The authentication service is unknown.

NTDS Replication 25/08/2014 5:00:57 a.m. Error 2513 Attempting to set the desired authentication protocol for a connection to the...