I *think* I have found what I want for my blog/journal/diary event management.
I decided that some sort of blogging software was possible what I wanted so I looked at a few and decided to have a serious play with WordPress, I actually already have a WordPress installation running which my daughter used for her round the world trip a year or so ago but I hadn't done more than install a basic system.
So, I've installed a new WordPress on my home server. I've chosen a Theme (like a skin) that I like which is fairly minimalist. This gives a reasonable look with the information being the important bit. WordPress has 'Categories' which do part of what I want rather well, I can post notes about, for example, insurance in the main thread of the blog and then, if I select category 'insurance' I see the sequence of notes about insurance.
However the real big plus is that WordPress has two or three plugins which implement event calendars where a blog posting is *also* an event which is inserted into an ical calendar. I haven't chosen which one to use yet but the presence of more than one is encouraging. It's as close to perfect as I could want really! :-)