[SM] I think it unlikely, but I don't know. [C,R,B] Neither Holy, nor Roman, nor an Empire a dam, nor a quarry, nor a barrow. Calling it partly man-made may have been misleading. A simple "no" might have been a better answer there also.
[CdM] Something like, in the sense that it would advise caution. (I have not actually seen the place myself to see just what warnings are posted, and haven't found anything on Google Street View.)
[T] It is an island, but [CdM] not Lindisfarne, because [R] it is indeed St Michael's Mount. Have this perspex replica of the Great Pyramid with St Michael's Mount inside.
Sorry for the delay. Distracted by thunderstorms and general torpor. (CdM) Not sea-level (Tuj) Despite the above remark, NO (Bis) NOT Radio Caroline (SM) NOT Al futures (Tuj) NOT fictional but maybe uncommon. (Raak) NOT scientific (CdM) Mineral connection NOT liquid.
(Raak) Already answered that. See Tuj (above). Still not fictional. (CdM) NO. Could be anywhere (on earth). (SM) YES, could be, but not its most common use.