My gpa is 3.1 of 4 from one of the best uni in Thailand.

I'm interested in MSc financial engineering, mathematical finance, quantitative finance, or financial mathematics.

I've studied 5 math subjects and my math grades are a, b, b+, c+, c+, respectively.

My IELTS is 7.0.

Pls recommend some uni that I have a chance to get in.

Thanks a lot.

Few users of this UK based forum will be able to relate to the information you have provided. I would suggest you approach a few UK Universities directly and enquire yourself.