Jewellery label moved; that will serve as a reminder (4,1,4)
I believe the answer is:
ring a bell
'will serve as a reminder' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'jewellery label moved' is the wordplay.
'jewellery' becomes 'ring' (ring is a kind of jewellery).
'moved' is an anagram indicator.
'label' with letters rearranged gives 'abell'.
'ring'+'abell'='RING A BELL'
'that' is the link.
Can you help me to learn more?
(Other definitions for ring a bell that I've seen before include "Town crier may" , "Seem familiar; toll" , "Call for servant" , "may awaken memories" , "jog memories" .)