Apex domains cannot have CNAME records.
Question and response
Question
dig abound.co.uk. NS
Answer
abound.co.uk. 5 NS ns2.nameshift.com.
abound.co.uk. 5 NS ns1.nameshift.com.
abound.co.uk. 5 NS lb9d7c.ns3.nameshift.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0