Show £1 note in court (7)
I believe the answer is:
concert
'show' is the definition.
(I know that concert is a type of public presentation)
'note in court' is the wordplay.
'note' becomes 'oncer' (oncer could mean the historical one pound note).
'in' means one lot of letters goes inside another.
'court' becomes 'ct' (abbreviation used in road names).
'oncer' placed within 'ct' is 'CONCERT'.
'ps1' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
(Other definitions for concert that I've seen before include "Musical performance" , "Harmony, performance" , "Public performance of music" , "Some entertainment" , "Musical event" .)