Quick summary. I have a 12 year old son who lived with his mother & stayed at mine over night for 1 night per week as of 7 years ago when we separated. Since then things have changed. I was never happy with his mum's behaviour & drug taking on a weekend however she appeared to be coping ok. My Son started not wanting to be at his mum's so I suggested that I should have him stay more which I did. I moved house so that he had his own bedroom. His mother than started dating a guy who I later found out to be on a methadone treatment plan. My Son took an instant dislike to him but his mum tried to force him to like him. My son started to want to stay with me more. So I suggested he stay with me 5 nights. She resisted but I said it is what my son wants. I then spoke to Social Services who did a background check on this guy & they found him to be a known drug user. I became increasingly worried for my son's welfare so I told me ex I would only allow him to stay over there 1 night per week & a few hours on a Sunday. I have had reports of drug dealers visiting the house, my sons PS4 games going missing & she seems to be struggling with money & relying heavily on my Maintenance payments even though my son is hardly there.

Anyway I woke up to a text from her boyfriend off of my ex's phone basically telling me that my son's behaviour is horrible & I need to have a word with him plus communication between me & my sons mum is very bad. I replied calmly that I will arrange for mediation to sort this out. She phoned me up crying begging me not to to apply for mediation.

I have phoned Family Lives for advice & the lady believes that I could go for full custody & bypass mediation. I think she said a C100 form? She said that I am doing the right thing & my son should be kept away from that household & environment.

I am not sure what to do as my ex basically said she will agree to anything if I don't go through mediation.

Shall I arrange for mediation even if she doesn't want it?