Trip horseman could make from Perth & Kinross — gee-gee’s knackered! (7,8)

I believe the answer is:

knight's progress

I'm a little stuck... Click here to teach me more about this clue!

'trip horseman' is the definition.
The definition suggests a singular noun which matches the answer.

'from perth kinross gee-gee's knackered' is the wordplay.
'from' indicates an anagram (the anagram comes from the same letters).
'gee' becomes 'g' (synonyms).
'gee' becomes 'g' (synonyms).
'knackered' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'perth'+'kinross'+'g'+'g'='perthkinrossgg'
'perthkinrossgg' anagrammed gives 'knightsprogres'.
'knightsprogres'+'s'='KNIGHTS PROGRESS'

'could make' is the link.

Can you help me to learn more?

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app