Sussex heir holds five records (7)
I believe the answer is:
archive
'records' is the definition.
(I've seen this before)
'sussex heir holds five' is the wordplay.
'sussex heir' becomes 'archie' (I am not sure about this - if you are sure you should believe this answer much more).
'holds' indicates putting letters inside.
'five' becomes 'v' ('V' can be a synonym of 'five').
'archie' going around 'v' is 'ARCHIVE'.
Can you help me to learn more?
(Other definitions for archive that I've seen before include "Save data for storage" , "Document or record collection" , "Document depository" , "Data repository" , "Store for historic records" .)