Fees for Domestic Adoption

Hi

Three years ago I began the lengthy process of adopting my wife's 3 kids. It began by me asking to have their surnames changed at the Amphur but was told this was the way to proceed.

Next week we go to Bangkok to officially sign the papers. Only last week they intimated that there will be administration fees. I have yet to get clarification from them as to how much this is so I was wondering if anyone on the forum had any knowledge.

Thanks

Liam