[URGENT] Applying for Visa inside of UK

Hello everyone,

I finished my A-level this June and I am going to Warwick at the end of this month, and to do so I need to get a new visa. I am from Hong Kong and I originally applied from here and my appointment to provide my biometrics is on the 11th, and only recently have I realised that I need to do a TB screening before that, and when I phone up the approved clinics they all said I won't be able to be tested until after the 11th. Since my old visa hasn't expired yet, I am thinking about entering the UK and apply when I get there instead.

I found out on the official site that there are things so called premium service centres (https://www.gov.uk/ukvi-premium-service-centres/overview) where I can get a visa quickly. I would like to ask if I can apply for a Tier 4 General Student Visa in these centres, and also if anyone did this before and how long will it take.