Apex domains cannot have CNAME records.
Question and response
Question
dig cc.strath.ac.uk. NS
Answer
cc.strath.ac.uk. 3 NS dns0.strath.ac.uk.
cc.strath.ac.uk. 3 NS dns1.strath.ac.uk.
cc.strath.ac.uk. 3 NS dns1.cis.strath.ac.uk.
cc.strath.ac.uk. 3 NS dns2.cis.strath.ac.uk.
Authority
The response has no authority records.
Additional
dns0.strath.ac.uk. 2 A 130.159.248.11
dns1.strath.ac.uk. 2 A 130.159.248.9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0