Like most questions with patents, the answer is "it depends". To know if an idea is patentable over prior art one needs carefully consider both the idea and the prior art. You can't divulge the invention here without potentially poisoning the ability to obtain a patent so we can't give you a definitive answer.
To be patented, your invention needs to be novel, non-obvious and useful. There are other questions on this site which deal with patentability so I encourage you to read them. Prior art is not limited to what is found in patents. You make the statement: "The existing one has never had a Patent applied for but relies on its IP." Since there isn't a patent, it isn't clear what IP you are referring to.
My advice is to do as thorough a prior art search as you can yourself using Google, Google Patents, or The Lens. When you find similar ideas in patents, follow the cited patents links to find other relevant art. Lastly, you should consult with a qualified patent attorney or agent to get a patentability assessment. It is my opinion, as an inventor, that an patent attorney or agent is well worth the expense.