My question is, just when and how did Mr. Biggles express an interest in diving? In my experience, families sometimes decide to all learn to dive together, but one (or more) family members were not a part of the decision, and those members are often not too excited, maybe even reluctant, to get involved. Making them do the course is not a good idea. Similarly, sometimes on a dive boat a diver will not feel right, or perhaps be a bit stressed over a dive, and not want to do it. As you know, we teach that you should never force that diver to do the dive. So back to Mr. Biggles. IF he expresses an interest in diving, and IF at the time of the dive he communicates, through word other sound or action no hesitation or undue stress, then he should join you. Other wise, not cool. Also, a plastic bag is no good- the claws thing.
DivemasterDennis