The first regular trips in many years to the depopulated Stroma Island (in the Orkneys) start this June, departing from John O'Groats-
https://stromawildlifecruises.com/
Very infrequent trips on 2 or 3 days a year ran up until Covid, but nothing since.
Stroma is the island you pass on the Pentland ferries service from Gills Bay to St Margaret Hope. It has always looked to be a pretty interesting place.