I can pre-define categories for members in 4.5 but they can't create their own category. option doesn't show at all. What setting have I got wrong?

You haven't got anything wrong. Members can't create categories in Blogs, Forums etc. That sort of infrastructure is created only by admins.

I'm sorry but what about this.

 

 

There are two things here:

1. Blog Categories - these are admin defined, and when a user creates a new Blog, they can choose from this list but not create a new one.
2. Entry Categories - these are user defined, and are defined per Blog, rather than globally.

Thanks,

I have just tried to create an RSS feed into Blogs but only gives me option of importing into Forums

34 minutes ago, Bethanyrayne said:

Thanks,

I have just tried to create an RSS feed into Blogs but only gives me option of importing into Forums

You can do this when editing the blog itself on the front-end: