'Copywrighted - do what? Is it anything to do with an association footballer of colour who used to advertise potted sauces - "It feels like chicken tonight"...'

Copywrighted refers to anything that's had an action performed on it by a copywright (cf. wheelwright, cartwright, Pricerite).

As in the example:

"Can you get some more paper clips from the store, please, Elsie?"

"Sorry, I'm a bit busy, love. I'll get the copywright to do it when she gets back from the photocopier."

(Taken from the abridged version of the Modern Dictionary of Bullshit, compiled by K. Henty (aka Melodeonboy). (Published by Chatup and Windbag 2008)