Apex domains cannot have CNAME records.
Question and response
Question
dig websiteserver.uk. NS
Answer
websiteserver.uk. 5 NS dns01.edge.fyfeweb.uk.net.
websiteserver.uk. 5 NS dns02.edge.fyfeweb.uk.net.
Authority
The response has no authority records.
Additional
dns01.edge.fyfeweb.uk.net. 5 A 45.85.194.2
dns02.edge.fyfeweb.uk.net. 5 A 159.242.64.35
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0