Not an apex domain
The domain ns5.p200.dns.uk-gov-cardiff-1.oci.oraclegoviaas.uk is not the root of its zone.
Instead, try zone transfer on uk-gov-cardiff-1.oci.oraclegoviaas.uk .
Instead, try zone transfer on uk-gov-cardiff-1.oci.oraclegoviaas.uk .