Apex domains cannot have CNAME records.
Question and response
Question
dig isware.co.uk. NS
Answer
isware.co.uk. 5 NS ns00.cyberspaceman.co.uk.
isware.co.uk. 5 NS ns02.cyberspaceman.co.uk.
isware.co.uk. 5 NS ns01.cyberspaceman.co.uk.
isware.co.uk. 5 NS ns03.cyberspaceman.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0