Authors not appearing

I’m having problems with the name of the authors NOT appearing on the posts as they should do. I recently set up 5 new author accounts after just being me on my own recently, and I had the problem with the admin name not working, fixed that, but now it seems only 1 author name appears on the first post on my blog, and if I refresh the page, sometimes another post will have the author’s name, but I’ve not had it so that every post has the author’s name attached as it should do. Please help me!?
The blog is http://www.ridestreet.co.uk
Thankyou!