"Bicycles will be removed" - legal?

The logical step would be to do this with a beater to a railing that we know the owner removes bikes from.

Then we sue them so that we can take a test case through the courts, pushing for a ruling that all such signs should be removed.

Slight hitch - if we lose, we have to pay all costs :-(

Does anyone know a lawyer that could give advice? I can ask my partner who is a barrister, but she mainly does european and commercial, not criminal stuff. Will run it by her anyway...

And if we lost said case it would be an end to cycle parking as we know it