Remove duplicate author picture, name, and post date from blog posts

I have a small site with few blog posts, and I have recently transferred from GP Marketer theme to GP Dispatch theme.

Since transferring, at the top of each post (before the first paragraph of text), a large (out of proportion) avatar picture is appearing, followed by author name, and data published - all bunched together and looking very ugly.

I am unsure on how to remove these?

Thanks in advance.