Thanks bliako, I shall look at LaTeX as I have had need to dynamically generate PDFs in the past. They are not needed for this application but no doubt I'll need them again one day.
Apropos your multiple templates dilemma. I would go with as many templates as possible if that would not hinder performance.
Performance really is not an issue here. The process of collecting together the information is quite slow as some of it calls web APIs. It is an ultra low traffic web page and, as they are done by CRON in the early hours of the morning, creating the emails is not something where time is important.
It was more the block of conditional subroutines that seemed to be a rather inelegant way of doing things.