School activities are not important in the UK, British universities only care about your grades and your academic interests. Your English is pretty good, I can understand most of what you said. No, it is not easy to get scholarships - most universities don't have any, and the few that do are very competitive. Oxford, Cambridge, LSE, St Andrews, UCL, KCL, SOAS, Edinburgh and Aberystwyth are all good for international relations. Many universities offer 'joint honours degrees' where you can combine international relations with business or economics.