Good university in Durham, say, to carry on without a break (5)
I believe the answer is:
segue
'to carry on without a break' is the definition.
I can't judge whether this definition defines the answer.
'good university in durham' is the wordplay.
'good' becomes 'g' (abbreviation).
'university' becomes 'U' (abbreviation for university).
'in' means one lot of letters goes inside another.
'durham' becomes 'see' (I am not sure about this - if you are sure you should believe this answer much more).
'g'+'u'='gu'
'gu' put into 'see' is 'SEGUE'.
'say' is the link.
Can you help me to learn more?
(Other definitions for segue that I've seen before include "Follow smoothly on" , "carry on" , "Follow on seamlessly" , "Play on" , "Change smoothly from one thing to another" .)
