If you are going to court then I think you have to show that you considered mediation but it won't work for you.
The process is - book an appt via Nation Family Mediation - just call them up and book one, they will find one close to you. It costs £95 I think.
I'd recommend doing it yourself so you get a slot that suits you, and its v easy to do and will save you solicitor costs on top of the £95. It can take a while to get an appt so its worth getting it out of the way early.
www.nfm.org.uk/index.php/about-nfm/contact-us
Then go to the meeting, and they will take down your basic details - date of marriage, name and DOB of any children, etc.
Then they will ask if you are willing enter mediation or not. In my case I explained that H is being very uncooperative, and that was enough for them (minimal reasons and no evidence really needed, its more down to your feelings and your personal wish not to enter mediation). They won't tell your H you have been if you don't want them to.
They agreed, and then sent me an official form which I sent to my barrister/solicitor.
I took along my relevant paperwork - marriage certificate and bank statements but didn't need any of it.