What is the process for certifying a British passport?

2 years ago I was told to go to the British Embassy. I believe this is no longer possible.

It has to be done by Apostille?

I am in UK at the moment travel to stay with my wife in Udon Thani.

What is the process if in UK, I have differing advice from various sources.

I am wondering if anyone has had recent experience with a civil partnership / same-sex marriage registration process in Thailand? If so, I really would appreciate some help with the paperwork process/ requirements. i am a UK citizen, and I know I will need a Marital Status Affiramation, however, when i go to apply on the ukgov site for this, it still says that civil partnerships are not recognised in Thailand, so i have hit a wall before i even start .... any advice/expereince?

DTV - got my bank account set up in LatAm. I'll have proof of financial stability. But my citizenship is in the US.

Are there any documents I need to get in the US for DTV? Apostille, etc?

Good Day

May anyone help,how does one get a South African Degree legalised in South Africa. Was told have to do SAQA and Dirco.This is for getting a visa.

Has anyone managed to do it and got the visa?The agencies say Thailand not an Apostille country!