lukey1979

My wife and I have 3 children that live with us, 1 daughter my wife has from a previous relationship and a Nephew and niece that my wife has legal gaurdianship over. All 3 live with us as our children, and their fathers have been absent since birth. Unfortunately all 3 kids have their Thai fathers names registered on their birth certificates.
I understand that in order to adopt these kids myself i would have to jump through masses of hurdles and I would be likely to encounter some sort of financial hurdle from their fathers. Im interested in domestic adoption as we are fixed into Thailand for the time being and I rarely go back to the UK  as I work abroad.
The children are 12, 11 and 5. I have searched through the forums and info websites on this issue and I want to know If when the child reaches a certain age (I hear 15) can they decide to change my wife and I as their parents legally and therefore change their name to mine without the huge red tape issue? Would it be a case of just going to the local Amphur and filling out some forms without the consent of their fathers etc?

Any help will be appreciated.

Thankyou.