I have extremely narrow feet, ankles and calves. I always buy my knee-high boots in the narrowest calf width from duo boots, which is 30cm at the widest point - just to give some indication of how slim we are talking.
But ankle boots are a real challenge. My current pair - ancient, from New Look - are finally giving up the ghost.
If anyone comes across any very slim, narrow ankle boots on their travels, please let me know!
Beggars can't be choosers. However - black or dark brown and flat or low heeled would be most versatile, although I'll also consider higher heels for a dressier pair as well! Lace-up is generally the best option as it gives me some scope to tighten them a bit, but the recent trend for very chunky boots tends to mean even these often look the wrong scale on me. Anything more dainty/delicate or very narrow would be great!