Apex domains cannot have CNAME records.
Question and response
Question
dig netweaver.uk. NS
Answer
netweaver.uk. 1 NS ns2.netweaver.uk.
netweaver.uk. 1 NS ns1.netweaver.uk.
Authority
The response has no authority records.
Additional
ns1.netweaver.uk. 1 A 77.74.199.4
ns2.netweaver.uk. 1 A 178.79.154.41
ns1.netweaver.uk. 1 AAAA 2a12:ab46:5344:62:0:0:0:a
ns2.netweaver.uk. 1 AAAA 2a01:7e00:e000:81b:0:0:0:b
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0