Argued about the high speed, indeed! (7)
I believe the answer is:
debated
'argued' is the definition.
('debate' can be a synonym of 'argue')
'about the high speed indeed' is the wordplay.
I cannot really see how this works, but
'about' could be 'a' (abbreviation in Chambers) and 'a' is located in the answer.
The remaining letters 'debted' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for debated that I've seen before include "Shared opinions" , "Discussed in public" , "Argued" , "Contemplated" , "Considered" .)