Hi. So i am studying at university of London external program and my first year grades were 1 merit, 2 credits and a pass (uk grades). My 2nd year grades are 3 distinctions. I am planning to apply at ivy league colleges and oxford and Cambridge.
My question is : will my first year grades be a hurdle? I have loads of extra curriculars (clubs, publications, internships at a law firm, volunteer work etc) to accompany my overall application.

Low grades could be of an issue when it comes to applying to top schools. However, what matters the most is your final GPA. You can justify the low grades you got in your first year by simply saying in your personal statement that you were working, doing internships, etc.