Do I need to transfer my education visa from my old passport to my new British passport before traveling to Bali and returning to Thailand?

Unfortunately, we are not going into the Bali consulate details. Sorry for removing those comments about consulate in Bali. That's what OP needs to find out.

If anyone has comment regarding to the original question, please contact one of the moderators to re-open this post.

thank you, everyone for your help

Make sure you know the Thai consulate in Bali is not available for visa services. It's only for Thai citizens. So you cannot get a tourist visa there.

There are two points you need to check

1. what is your current stamp, a) extension of stay or b) the first 90 days from your initial visa?

2. Are you going to apply for a new Non-ED for the advanced/sequel course to the current one from the same school?

- IF the answer to 1 is b), you cannot transfer the stamp. just leave as planned.

- IF the answer to 1 is a) AND 2 is No, you have to transfer your extension stamp and then cancel the current extension before you leave. Especially if you are seeing to leave or enter through a land border.

- IF the answer to 1 is a) AND 2 is Yes, you can leave without transfer stamps and may not have issue unless you go through a land border.