GIBRALTAR – A historic post-Brexit deal comes into action next week, when residents of Gibraltar will be able to stroll across into Spain and surrounding Europe without any checks or restrictions. Long queues for the double police checkpoints where travellers have had to present passports to officials from both Spain and the British overseas territory will be gone when the land border disappears forever next Wednesday. British citizens living on “the Rock” will be able to travel anywhere in the Schengen area without being subject to the post-Brexit rule that restricts Britons to staying only 90 days in every 180…