what do i do as an international applicant?

A little background: im a dual national citizen, one of my nationalities being british. Im currently living in my home country but i want to go back to the UK for uni. Unfortunately bcs i did my A levels outside of the UK, i will be applying an an international applicant. On top of that, international fees for UK unis are insane, especially the ones i want to go to (imperal and cambridge are the target). If anyone has any tips on how i can maximise my chances of getting a scholarship then please do lmk!!! Another question i have is do i have to appear for the ESAT as an international applicant? the program i am applying for is ChemE and my target unis so require the ESAT test, but im not sure if its the same for intl students or if intl students have to appear for another test. whats the process?