why is add new section button appearing in middle of section?

Hi

I am having a problem while designing a new site. This site was initially on 7.0 and I am upgrading each page and adding new sections for the design. I seem to get so far and then when I try to add a new section, the button either disappears or is in the middle of a previous section. I can't edit the section, move it or change the padding. Even when I do manage to change the padding I still get a large gap at the top. This seems to be after about 2 or 3 sections have been added successfully and saved. But, the issue then remains, during different sessions etc. after I leave it a while or even log out. 

All of the core pages on the website have been updated successfully with no issues. I am now working on individual branch pages that are not in the navigation, either starting from scratch or adapting what was there, and every one I have tried is having the same issue. I am tearing my hair out. 

Certain sections of a page also go out of alignment with no apparent reason, with text going to the far left outside of the usual grid area, sections of text are all hyperlinked when only a word was linked, and even if I can add a section, I can't then edit it as there is no option to add a block. When I go to edit mode it's looking fine. 

I have removed any CSS that was on the site and individual code injections in case that was causing a conflict but am still experiencing the same issues. 

Has anyone else come across this before or can you offer any advice? 

password for the website link is MAgikatsnew for reference.