Tend to race back to Home Counties (5)
I believe the answer is:
nurse
'tend to' is the definition.
(I've seen this before)
'race back to home counties' is the wordplay.
'race' becomes 'run' (run is a kind of race).
'back' is a reversal indicator.
'to home counties' becomes 'se'.
'run' written backwards gives 'nur'.
'nur'+'se'='NURSE'
(Other definitions for nurse that I've seen before include "One caring for patient" , "Carer for the sick; shark" , "One tending the sick" , "Nourish" , "Medical carer" .)