Hi LOOSHMA and welcome to the forums.
The way things work in the UK is that you have to be "lawfully and permanently" in the country to be entitled to services via the NHS. So if you were in the UK as a properly accredited student, then you would be entitled to use NHS services. You would need to register with a GP and then probably be referred to specialist diabetic services as a T1. Whether or not you were prescribed a CGM would be a decision for your relevant clinical professional to make.
Hope that's useful.