"The posters on these threads who say "I'd look gaunt/skeletal/skinny if I went under 11.5 stone" - in pretty much all cases this is not true. You're just not used to seeing yourself at a normal weight."
I'd look absolutely fine (and be at a healthy weight for my height) at 11 or 11.5 stone and have been that for large chunks of my life, I would definitely look gaunt at under 10 stone, which would still be a normal BMI. I was last that weight as a teenager and I was the kid that everyone asked if I was eating enough - I had no hips, no boobs, lots of visible boniness, and didn't get my period til I was 15 (I actually did eat enough, was just one of those teens who grew up before they grew out and I hated being so "undeveloped"/beanpolish). That isn't just "I have no idea what normal weight looks like!", I was really very, very thin, much thinner than many of my peers while still being a "normal" weight.
Obviously it's a good idea to be in the healthy weight range for your height (with caveats re fat, muscle mass) but there's no requirement to be at the bottom end of it, or any indication that that's "even healthier", and for certain frames (mine, for instance) the lower end does look bad. My sister is a 6 foot tall size 10, super fit, looks amazing, she's still hovering around the middle/top of her healthy BMI range. We weigh heavy, our family.