Apologies it clicked just after I posted my last reply that I needed to execute the namesctl.exe which I've now done

Got the following errors -
NNL-00024: warning: no preferred name servers in SQLNET.ORA
NNL-00018: warning: could not contact default name server
Welcome to NAMESCTL, type "help" for information.

Are these critical errors? I've just checked my other db which works and it throws the same errors?

Have attempted to register my db

now getting error
Response status: NNC-00406: name "FastCont_BackUp.nat.bt.com" does not exist