In helpful spirit, one financing our competitor? (8,5)
I believe the answer is:
guardian angel
'one financing our competitor?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'in helpful spirit' is the wordplay.
'in helpful' becomes 'guardian' (I can't explain this - if you can you should give a lot more credence to this answer).
'spirit' becomes 'angel'.
'guardian'+'angel'='GUARDIAN ANGEL'
(Other definitions for guardian angel that I've seen before include "Benevolent spirit" , "Person concerned with the welfare of another" , "Protecting spirit (in this paper?)" , "Protector (ours?) - city vigilante" , "Person keeping an eye on one's safety (including a newspaper)" .)