mediation, house and children

I helped my new partner through his divorce/Consent Order and now it is my turn.

I was with my ex for 21 years but we never married. I left our home at his request 4 years ago and have been unable to see one of my children since and briefly seen my other 2 children a couple of times due to threatening behaviour on his behalf. I tried once to meet my youngest at her school with her consent but the school phoned my ex and I had to leave because I was scared as he had threatened my new partner on numerous occasions.

The house is in his sole name but I have proof I paid for an extension and have messages where he says he will pay me back. However because it is the children's home I have not yet gone down that route. He previously agreed to mediation if I paid and I see Wikivorce do mediation for £185. I would need to sort out seeing my disabled child, being involved in decisions for his care and what would happen if anything happened to my ex in the future (he already had a health scare last year)as I would not want him to go into care.We both want to keep solicitors out of it.

Would the Wikivorce mediation service be suitable for unmarried couples and for the reasons of the children and housing issues?

Just to add the children are all over 18 now.