I don't see any mandatory requirements for health insurance on the Government website

https://www.gov.uk/foreign-travel-advice/british-virgin-islands/entry-requirements

I did see it on the moorings website, but am assuming Moorings is requiring it not the government. Hopefully there will be more rapid testing sites on Tortola in the near future. So far I've seen you can get at Peebles Hospital and somewhere else across from TMM I think they said. Someone also said you could get tested on VG and Jost but did not clarify specifically where . . . .

I also found this regarding Gold Seal requirements: https://www.bvitourism.com/sites/default/files/reopening-guide.pdf

I guess you would have to call your lodging and ask, maybe it is not enforced?