Relocating with my children

[Kellyfgp]

Has anyone been to court to be able to relocate with their children? How did it work what is the likely outcome if I was to do this?
I've been separated from my children's father for 3 years we've never been to court over access he just has them on a Saturday 12-6 I continued to stay in this area although this is not where I am from so have no family or anything here so I'm not happy
Me and their father do not have a good relationship (hes very verbally abusive) can sometimes get slightly physical on his behalf which is obviously distressing for my children as they are not use to seeing this kind of behaviour we agree that all communication goes through his mum who I have a good relationship with (he doesn't) and no face to face contact between me and the father is necessary as causes me great upset... he sticks to this when it suits him
My fiance has relocated to scotland with work and me and the children are wanting to relocate with him. Financially we will be better off and mentally I believe I would be too which in turn means a better life for my children. I in no way want to stop or cause a barrier between my children and their father. ( he currently has no contact with them other than his few hours on a Saturday.due to his inappropriate behaviour I would be happy to put forward contact of every 3 weeks for a weekend half of the summer holidays and half of every half term for him to have them.
Does anybody know exactly what I need to do in order to put these plans forward to him?
Tia