Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-59.co.uk. NS
Answer
awsdns-59.co.uk. 5 NS g-ns-1534.awsdns-59.co.uk.
awsdns-59.co.uk. 5 NS g-ns-379.awsdns-59.co.uk.
awsdns-59.co.uk. 5 NS g-ns-955.awsdns-59.co.uk.
awsdns-59.co.uk. 5 NS g-ns-1855.awsdns-59.co.uk.
Authority
The response has no authority records.
Additional
g-ns-379.awsdns-59.co.uk. 5 A 205.251.193.123
g-ns-955.awsdns-59.co.uk. 5 A 205.251.195.187
g-ns-1534.awsdns-59.co.uk. 5 A 205.251.197.254
g-ns-1855.awsdns-59.co.uk. 5 A 205.251.199.63
g-ns-379.awsdns-59.co.uk. 5 AAAA 2600:9000:5301:7b00:0:0:0:1
g-ns-955.awsdns-59.co.uk. 5 AAAA 2600:9000:5303:bb00:0:0:0:1
g-ns-1534.awsdns-59.co.uk. 5 AAAA 2600:9000:5305:fe00:0:0:0:1
g-ns-1855.awsdns-59.co.uk. 5 AAAA 2600:9000:5307:3f00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0