Welcome to GN's Jewelee, cannot advise of parking restrictions but all free camping around ferry terminal is a highly sought-after prize that cannot be guaranteed for a particular date. Always have a Plan B to avoid disappointment.
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Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan
Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.
I'm not familiar with the location you mention but, frankly, I would not camp under the Westgate bridge simply for reasons of personal safety and I'm no wimp about such things.
I have a spot which I don't wish to broadcast to the world but will PM to you, nudge me if I forget.
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"I beseech you in the bowels of Christ think it possible you may be mistaken"
Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland
At the last terminal, we just parked in nearby streets without problems, or used free camps up to an hours drive out.
Same plan would apply at the new terminal. Certainly wouldn't be paying for it.