Choosing a sixth form

Hii, I'm a Sri Lankan student who's moving to England next year for sixth form. I'm currently doing my IGCSEs and I have good predicted grades. For my a-levels, I want to do bio, chem, physics and cs. I'm looking into a good state mixed sixth form in london. I've been looking into woodhouse college and would love to go there too. I'm really grateful for any advice or options anyone has on the application process and just choosing a sixth form in general, especially as an international applicant.
thanks soo much!

harris westminster sixth form is litch in the middle of london. highly recommend! its a selective mixed (boys&girls) state school btw

thank you so much!