Mobility aid for part of foot caught in toilet lock? (10)
I believe the answer is:
wheelchair
'mobility aid' is the definition.
(I've seen this before)
'part of foot caught in toilet lock?' is the wordplay.
'part of foot' becomes 'heel' (I've seen this before).
'caught in' means one lot of letters goes inside another.
'toilet' becomes 'wc' (W.C. is an example).
'lock?' becomes 'hair'.
'heel' put within 'wc' is 'wheelc'.
'wheelc'+'hair'='WHEELCHAIR'
'for' acts as a link.
(Other definitions for wheelchair that I've seen before include "Mobility aid" , "Invalid's transport" , "Invalid transport" .)