I am Not sure Gruniard island is available as some Russian Ogliarchs were after it a few years back, I was amazed how close to the mainland Gruniard was, It looked like only 500/600 metres at the nearest point
When I was up there you could read the warning sign with a pair of binoculars, interesting that the Decontamination seemed to consist of spraying salt water over the island to kill off the anthrax spores. Rabbits must have inbuilt immunity as there were loads of them.
Rockall is available though, this was climbed and claimed for the UK to help with fishing and mineral rights in 1955.
May the Ford be with you