[Transferring domain to Hawkhost: "Enter the Tag name of the new Registrar"]

I am Transferring an old domain to Hawkhost: the old provider is asking me the following information
"Enter the Tag name of the new Registrar". 

Does anyone know what value to insert here as I couldn't find it on the existing online resources. 

EDIT++ Tag name This is a unique name given to any registrar dealing with .UK domains. This can be determined from your new Registrar.
Thanks