Substitutes with obligations to secure record (8)
I believe the answer is:
deputies
'substitutes' is the definition.
(I've seen this before)
'obligations to secure record' is the wordplay.
'obligations' becomes 'duties' ('duty' can be a synonym of 'obligation').
'to secure' means one lot of letters goes inside another.
'record' becomes 'ep'.
'duties' placed around 'ep' is 'DEPUTIES'.
'with' acts as a link.
(Other definitions for deputies that I've seen before include "Stand-ins or next-in command officials" , "Persons authorised to act as substitutes for others" , "Political representatives" .)