One cross-channel article and another occupying leasing firm (11)
I believe the answer is:
unrelenting
'firm' is the definition.
(thesaurus)
'one cross-channel article and another occupying leasing' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'un' (northern English dialect form of 'one') and 'un' is present in the answer.
'cross' could be 't' (shape) and 't' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'another' could be 're' (I've seen this in other clues) and 're' is located in the answer.
'occupying' could be 'in' (to occupy a building is to live in it) and 'in' is found within the answer.
The remaining letters 'leg' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for unrelenting that I've seen before include "Inexorable" , "Not yielding in severity" .)