Apex domains cannot have CNAME records.
Question and response
Question
dig 45.26.195.in-addr.arpa. NS
Answer
45.26.195.in-addr.arpa. 5 NS dns2.wavenetuk.net.
45.26.195.in-addr.arpa. 5 NS dns1.wavenetuk.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0