Having been referred to by as "plump," went to see (6,5)

'having been referred to by' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'plump went to see' is the wordplay.
I cannot quite see how this works, but
'plump' could be 'round' (plump can mean round or full) and 'round' is present in the answer.
'went' could be 'led' (leading is a kind of going) and 'led' is located in the answer.
'see' could be 'c' (the word for the letter, according to Chambers) and 'c' is located in the answer.
The remaining letters 'al' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

'as' is the link.

Can you help me to learn more?