Offensive when company replaces one for seeking advice (10)

'seeking advice' is the definition.
(I've seen this before)

'offensive when company replaces one' is the wordplay.
I cannot quite understand how this works, but
'when' could be 'on' (I've seen this in other clues) and 'on' is found within the answer.
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
This may be the basis of clue (or it may be nonsense).

'for' acts as a link.