You will want to make sure that your cv is absoloutely clear about your skills - right at the start (employers do not want to have to make any assumptions, or read the detail of the cv when they are doing the first cut).
So an explicit personal statement right at the beginning that states: x years experience in [industry], extensive experience in project management etc...
Then have a serious look at your job titles.
If you job title was for example, Research Officer, then your longer description of the responsibilities including managing a project, a potential employer may miss that on a first read through. You do have to be scrupulously honest about the activities of your role and the skills you have, but you could put your job under the heading of Project Management - scientific officer.
Difficult to explain in abstract - if you pm me your cv I could have a look, if that would help.
In my experience, you don't need PRINCE to practice as a project manager in most parts of the public sector but it gives them reasurance if you are qualified and may give you an advantage over other candidates.