Two of Barbirolli's pieces reversed in order? It might have saved someone turning over (7)
I believe the answer is:
rollbar
'it might have saved someone turning over' is the definition.
(bar which strengthens a car if it overturns)
I cannot understand how the rest of the clue works.
(Other definitions for rollbar that I've seen before include "Sports car safety feature" , "protection for drivers" , "safety feature on vehicle" , "Protection if car overturns" , "Maybe one resisting turnover" .)