Didn't take a pic of it unfortunately, but... when spraying paper based things with polyurethane varnish, many thin coats are better than one heavy smooth one.... the varnish soaked into the gate sticker, compromising the adhesive and causing the paper to expand, and creating wrinkles, these subsided slightly as it dried and i was able to press the paper back down to get rid of most of the wrinkles.
However, in the process it smudged the laser-printed design (possibly the solvent in the varnish interfered with the bonding of the ink).
So i peeled it off and scrapped it.
This lesson being learned, i went much more gently on the base and it turned out fine (if slightly greener than expected).
I will try to apply a new sticker to the gate tonight.