So the chap on the outside is the TV lawyer (5)
I believe the answer is:
mason
'the tv lawyer' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'so the chap on the outside' is the wordplay.
'so' becomes 'as' (I've seen this in other clues).
'the chap' becomes 'mon' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on the outside' is an insertion indicator.
'as' inserted into 'mon' is 'MASON'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for mason that I've seen before include "US comedian" , "one wearing an apron" , "one in construction" , "Construction industry employee" , "One works with stone or brick" .)