The sporty stuff is good to do anyway, as is the D of E Award Scheme. As a CV builder though, it has more application to the RAF than to civil ATC. The reason is that the RAF is picking officers (and senior NCOs for ATC, but your mate's question was about being a pilot, and they are all officers) first and foremost. Their specific branch, and thus profession, is secondary.
Having said that, if I were a recruiter for NATS I'd also be more impressed, all else being equal, with a candidate who was active in sports and community activities rather than simply watching TV and surfing the 'net. More important in the long run is what those activities do for you. If they help you grow as a person, experience more from life and help others, you will have a fuller life whether or not you get into ATC.
It sounds to me as if you have a pretty full calendar already so though I would suggest a refresher on English (that is friendly advice; please, no flaming), I see no reason why you wouldn't put the interviewers in a positive frame of mind before the interview starts. Have a look at the NATS website and maybe some of the overseas ATS providers, for example DFS of Germany, for samples of the type of testing that is purely pass or fail and comes before an interview.
Good luck.
