Toffs, like that posh fellow Leslie (6)
I believe the answer is:
nobles
'toffs' is the definition.
The answer and definition can be both people as well as being plural nouns.
Perhaps there's a link between them I don't understand?
'that posh fellow leslie' is the wordplay.
'that posh fellow' becomes 'nob' (I can't explain this - if you can you should believe this answer much more).
'leslie' becomes 'les'.
'nob'+'les'='NOBLES'
'like' acts as a link.
Can you help me to learn more?
(Other definitions for nobles that I've seen before include "Aristocrats" , "Members of the aristocracy" , "Men of high rank" , "Former Eng. gold coins" , "Members of Lords" .)