Stalwart Tory earl shunned by Camilla and her old man, mistakenly (6,9)
I believe the answer is:
Here is my best explanation:
'mistakenly' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'stalwart tory earl shunned by camilla and her old man' is the subsidiary indication.
I cannot quite see how this works, but
'tory' could be 'r' (abbreviation for right) and 'r' is located in the answer.
an anagram of 'camilla' is 'acmilla' which is located in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is present in the answer.
'man' could be 'hal' (I've seen this before) and 'hal' is present in the leftover letters.
This explanation may well be incorrect...