Hi Tashbox87
I have recently discussed this issue with a solicitor. My ex was abusive to me during our marriage, and we divorced 7yrs ago. I now have a wonderful partner and although my ex sees his girls, he is now mentally abusing them, and I have stopped them from visiting him as they are getting too upset. Anyway...she told me that if I want to move in this country, I can, but I have to have his permission to take the children abroad. However, if you told him your plans, and he didn't agree, he would have to take you to court. The minute you explain the situation, and the involvement of drugs, the judge would more than likely side with you. I can't guarantee that, but this is what I was told. You need to make sure you have any evidence of drug use, and his unreasonable behaviour, as this will be considered damaging to your son. Your best bet is to see a solicitor for a fixed fee advice session (some solicitors offer this for me, unfortunately not where I live and the hour has cost almost �100, but is worth it if you can manage to pay for it)
I hope this helps, and please let me know if I can help anymore. Take care.