You should never be worried about telling the truth. A reality is that it is very rare for any flight school to get absolutely no negative feedback. Aeroplanes break, instructors become unavailable and very often (not in your case) candidates blame the school for their own failings. Offset against that there are some absolutlely horrendous ATOs (mostly in Europe and the US) that if their Aviation Authorities were any good would be shut down tomorrow; rules bent, rules ignored, students coerced into operating unserviceable aeroplanes... you wouldn't believe. Stapleford are, in my experience, one of the good guys. I would hope your experience was just an unlucky outlier. I think S-works is saying the same thing in a slightly different way.