GWR work nothing like the pattern above, just because one TOC works like that doesn't make it reflective of any other at all. Borders on unhelpful to suggest that's the pattern if you don't know.
GWR Delays are MS grade working avg 37hr 5 day week. Work earlies 6-2 and lates 2-10. There are nights but that was until very recently, and probably still is, in its own dedicated link.