Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-62.co.uk. NS
Answer
awsdns-62.co.uk. 5 NS g-ns-382.awsdns-62.co.uk.
awsdns-62.co.uk. 5 NS g-ns-1539.awsdns-62.co.uk.
awsdns-62.co.uk. 5 NS g-ns-1218.awsdns-62.co.uk.
awsdns-62.co.uk. 5 NS g-ns-958.awsdns-62.co.uk.
Authority
The response has no authority records.
Additional
g-ns-382.awsdns-62.co.uk. 5 A 205.251.193.126
g-ns-958.awsdns-62.co.uk. 5 A 205.251.195.190
g-ns-1218.awsdns-62.co.uk. 5 A 205.251.196.194
g-ns-1539.awsdns-62.co.uk. 5 A 205.251.198.3
g-ns-382.awsdns-62.co.uk. 5 AAAA 2600:9000:5301:7e00:0:0:0:1
g-ns-958.awsdns-62.co.uk. 5 AAAA 2600:9000:5303:be00:0:0:0:1
g-ns-1218.awsdns-62.co.uk. 5 AAAA 2600:9000:5304:c200:0:0:0:1
g-ns-1539.awsdns-62.co.uk. 5 AAAA 2600:9000:5306:300:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0