The family clearly had religious roots, which was fairly common in Wales at the time. Henry, who presumably was raised locally on the island, would have been born following the 1905 Welsh Revival, which was the largest full scale Christian revival in Wales in the 20th century. As a result around 100,000 Welsh nationals became Christians, but despite this it did not put a stop to the gradual decline of Christianity in the country, only holding it back slightly. Many of the chapels that the Williams-Lewis household would have congregated simply no longer exist or have long since been deconsecrated. It’s entirely likely that I’ve explored some of them!