Sandy going round London university in a day, giving deceptive impression (5,4)
I believe the answer is:
false dawn
'deceptive impression' is the definition.
The definition suggests a singular noun which matches the answer.
'sandy going round london university in a day' is the wordplay.
'sandy' becomes 'fawn' (I've seen this before).
'going round' indicates putting letters inside (some letters go around others).
'london university' becomes 'LSE' (London School of Economics).
'in' indicates putting letters inside.
'day' becomes 'd' (abbreviation for day).
'a'+'d'='ad'
'lse' going within 'ad' is 'alsed'.
'fawn' going around 'alsed' is 'FALSE DAWN'.
'giving' acts as a link.
Can you help me to learn more?
(Other definitions for false dawn that I've seen before include "Light before sunrise" , "Leads fawn into illusory light or deceptive beginning" , "transient light?" , "Promising situation that comes to nothing" , "time of illusory promise" .)