iTunes Artists not being sorted properly

This has happened on a few of my artists on iTunes. I like to have an organised iTunes so for this to happen really bugs me haha! I am quite comfortable in using iTunes but for some reason when some of my artists are split into different ones when they are quite obviously named the same. Example below;

I have checked "Get Info" and everything is correct and the same. Has anyone else had this problem? I need help as its happened to several of my artists and its quite annoying.

Thanks!