this kind of stuff bothers me too
luckily i;m mostly recovered (i eat proper amounts but i'm still preoccupied by my body, think i'm fat, concearned with calories etc). but i still worry my housemates notice my weird food habits (sweeteners, everything "light" and low fat etc, weighing food so i can count calories). in the end i stopped caring and stopped hiding my habits, they probably think im weird but i am. i actually told one of my housemates in the end as well, as it came up, and we were quite close. she understands and is much better to talk to than a lot of people, never says any of the wrong things other people have said. i hope your friend is as thoughtful and helpful when you need support.
good luck with getting treatment, i know how hard it is in the UK. its usually quite easy to get councelling through the NHS or uni tho - you dont have to recover, just go and talk.
p.s. i like how when you described bulima it looks as if you;re saying it;s normal lol