Spies administrator leaving lines on toilet (6,6)

I believe the answer is:

secret agents

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

'spies administrator' is the definition.
'secret agents' can be an answer for 'spies' (I've seen this before). I'm not certain of the 'administrator' bit.

'lines on toilet' is the wordplay.
'lines on' becomes 'secreta' (I can't justify this - if you can you should believe this answer much more).
'toilet' becomes 'gents' (I've seen this before).
'secreta'+'gents'='SECRET AGENTS'

'leaving' is the link.

Can you help me to learn more?

(Another definition for secret agents that I've seen is " Spies".)

I've seen this clue in The Independent.

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