Using others' dissertation theme and layout I have been working on my dissertation and when doing the literature review I stumbled across another dissertation with similar research ideas as myself. 

When reading it I reallly like the layout and structure as they based it around a specific well known framework. I have found myself using a similar layout and theme but with my own content, data collection, analysis and findings. 

Can someone confirm if this is ok? Or will I need to restructure it?
Within reason, the general structure and format of a research document is not really something that can be protected by copyright and is not really subject to copyright. You shouldn't run into plagiarism issues, either.

However, if you very closely mimic the organization and layout of a thesis, you should at the very least acknowledge the source to which you are indebted for the structure of your thesis with a citation.