Hello again and thanks for the extra info.
1) Going to court - The legal action route would be to apply for a child arrangements order in the family court in the locality where your son lives in the UK.
The court form you would need is a C100, here:-
The court fee is £215.
The court would be likely to order that you should have some form of regular contact with your son, becauase it is government policy that it is good for children to have contact with the parent that they do not live with - unless there is very good reason indeed why that should not happen.
However, not only would this be difficult for you to do as you are not living in the UK, but also, even if you got the court order, it would be very difficut for you to enforce if your boy's mother did not comply, because you would have to bring the case back to court again.And of course all this is very expensive.
You would not get an order saying that your son should live with you, because that would be far too disruptive for your son, as he has always been cared for by his mother, so I am glad you are not considering that.
2) Child support. I do not recommend that you stop paying child support a) because the money is for the benefit of your son b) because if you stop, you give the boy's mother the opportunity to say to your son that you care so litttle for him that you have stopped sending money c) in UK law, child support is always due to be paid by the arent that the child does not live with, regardless of whether or how much they actually see the child. It's separate legislation - child support is governed by the Child Support Act 1991, and contact with a child is governed by the Children Act 1989.
3) REUNITE INTERNATIONAL The best that I can suggest is that you contact the charity Reunite International. http://www.reunite.org/
They specialise in everything to do with children living in a different country to one parent. Their advice line is: +44 (0)(###) ###-####234
They also offer a speciaist mediation service by telephone for eg contact with a child in another country
I have been to talks given by Reunite and I can confirm that they are really expert in international issues concerning children.
4) As you are named on your son's birth certificate, that means in UK law that you have parental responsibilty. Although this is largely symbolic, it does mean that you have the right to be kept informed of your son's educational progress. So - with a copy of your son's birth certificate, and proof of your own identity, you could write direct to the headteacher of your son's school (if you know which school he's at) and politely ask to be included on their mailing list for all school events, and to receive a copy of his annual school report each year. I know it's not much, but at least then you'd know how he's doing.
I'm sorry I couldn't give you a moer positive answer but I hope this helps anyway and I wish you the best of luck.
Thanks and best wishes...