If I recall correctly, Barbara's father is a clergyman. Perhaps he is being posted abroad, hence the need for a quick wedding. I'm sure Patsy has caught the first ship back to Blighty, hence why Delia hasn't heard anything of her. I thought the handling of the thalidomide story was excellent, apart from the line about the parents not having a map, which reminded me of the modern "Welcome to Hollamd" that a lot of parents of special needs children find patronising.
It will be interesting to see how the nuns react to Trixie's divorced suitor. Ordinary people were very disapproving in those days, let alone people from a religious order.