Done up/stiched up like a kipper, surely takes it's meaning from the term red herring, which means to mislead or distract from an important issue, in a trickster style.
A Red Herring, in the literal sense, is a particularly strong smelling fish called a Kipper that has turned a red
colour following the
smoking process traditionally used to preserve it.
Therefore, to be
done or stiched up like a kipper, clearly means to be duped or tricked by false information that was there for all to see, (in hindsight).
For example: when someone purchases an item they believe to be far
superior to what it turns out to be, based on the persuasion and false information by the seller.
He was done up like a kipper when he bought that
car. Meaning the
car was a pile of s*** and he was tricked when he payed top dollar for it.