They teach British pronunciations and spelling of English in Pakistan but the accent is still ethnic Pakistani accent depending upon in which part of Pakistan you to go to school. Like Sindhi students will have Sindhi accent , Punjabi will have Punjabi accent , a Pathan student will have a Pashto accent and Urdu speaking people have that bhaia accent of English. No matter which school you go to you will not have that authentic British , American , Australian accent. In USA they offer accent reduction courses and I am thinking to enroll in one.
There are some who do it online. Basically, you can see them and you do an online meeting. Works really well. I did an initial class where the teacher analyzed my speech, and then she made a customized lesson plan for me. I was only able to do one class, I got a new job soon after and had to travel a lot.
She pointed out that I don't pronounce the K, C, T, D and S sounds right, and told me these are pretty common amongst her other Pakistani students.