I don't think there is a catch. Some lawyers are genuinely concerned about the situation regarding legal aid and people not being able to afford legal representation. John Bolch does sessions at the University of Kent Law Clinic to those who can't afford legal representation so he is committed to helping and qualified to write these eBooks..
BTW to avoid any doubt I'm not a lawyer or any other divorce professional.
Divdad, There are lots of helpful divorce sites out there. Look under your wiki divorce services for lots of links. Not fair to only point out one!
Also re your Q on mediation. Any order or agreement signed and dated by the persons involved are not legally binding until the court order says so.
You can apply to contest or amend at any point prior to the legally binding court order - Very expensive - So be clear from the start and communicate to keep costs down!