Race with dear Charles hiding in shelter (12)
I believe the answer is:
steeplechase
'race' is the definition.
(steeplechase is a kind of race)
'dear charles hiding in shelter' is the wordplay.
'dear' becomes 'steep' (I've seen this in another clue).
'charles' becomes 'Chas' (shortened form).
'hiding in' is an insertion indicator.
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'chas' inserted inside 'lee' is 'lechase'.
'steep'+'lechase'='STEEPLECHASE'
'with' acts as a link.
(Other definitions for steeplechase that I've seen before include "Non-flat horse race" , "Horse race with jumps and ditches" , "run?" , "Horse race with ditches and hedges" , "Type of horse race" .)