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