Flown that 105 a fair bit, but for Bond. No idea that BCAL had it before them or was it on loan? As regards the thread, the sovreign is probably the easiest offshore lighthouse to land on and a normal offshore approach and departure will keep you good, however the bird droppings will not endear you to any of your guests! The smell(if it has not been manned for a few years) will seriously make you gag and if the deck is wet.......
If your looking for difficult, try the sevenstones lightship on a neap tide!! Good luck