Yes, a permit is required for professional photographers to use a tripod.
The first shot was taken with a minipod balanced on the handrail of the balcony, where no-one is permitted to use a tripod because of commuter traffic.
Great shots, the 17tse is perfect for there. I got a day permit to shoot there about 5 yrs ago and got a great little tour to boot. An mta guy took me through the catwalks between those back three windows in your 1st photo. love the last shot