What country are you in? What is “sixth form”? Don’t you think you should ask this question in a forum where you live?
I am in the U.S. and I paid $380.00 USD per hour for a patent attorney.
Before you do that you MUST READ this book. It will save you a lot of time and money on items that either already exist or won’t sell. I had lots of good ideas and this book showed me how to avoid wasting my time on ideas that would not sell. And the book is less than $20.00. A real bargain.
The book is “Will It Sell? How to Determine If Your Invention Is Profitably Marketable (Before Wasting Money on a Patent) “