Little chap following pipe down sandbank (5)
I believe the answer is:
shelf
'sandbank' is the definition.
(thesaurus)
'little chap following pipe down' is the wordplay.
'little chap' becomes 'elf'.
'following' means one lot of letters go next to another.
'pipe down' becomes 'sh' (I've seen this in other clues).
'elf' after 'sh' is 'SHELF'.
(Other definitions for shelf that I've seen before include "Ledge on which to stand items" , "Sill" , "A place to store" , "Projecting layer of rock" , "grass down under" .)