I've actually just burst into tears. Thank you so much for your kindness especially.
Aww - I'm sorry to make you cry! Just be glad it was from kindness though, and not my Big Stick 
I feel a bit silly, keto was sold to me as a super speedy way to lose the weight, some even claiming i could lose 3 stone within 4-6 months. Which seemed madness but it would make such a huge difference to my life if that was the case.
Bootcamp isn't keto. Keto is super strict, and limits carbs to 20g per day. On Bootcamp we don't count the carbs, but by focusing on lower carb veg and salad (as well as avoiding higher carbohydrate foods in general) that's how we lose the weight.
If you assume a 2lb loss per week, that's 8lbs a month - so let's round that down to 7lbs/half a stone. Therefore 3 stones will take you around 6 months to lose. However some people lose at a faster rate, especially when they have more to lose, so that's a 'best guess'
Perhaps I've been misled and had my hopes raised way too high
Possibly! I can't really comment, because I don't know enough about keto.
What I would say, though, is that this is a marathon not a sprint. The weight didn't just suddenly go on, so it stands to reason it's going to take a while to shift. (It's also a maddening fact that it seems to go on faster than it will disappear!)
Best advice I can give you is to keep your focus on the short term - if you keep thinking about the 6 stones you want to lose, that can seem overwhelming. So think about the next half stone, or seeing the next lower number on the scales - I don't know how much you weigh, but for me, my first target was getting under 150lbs (which is 10 stone 10lbs). My next target is to lose half a stone, and my next one after that is to see the scales start with a 9 rather than a 10. Each target is only small, but it makes it seem much more achievable and within my grasp.
I'm roughly hitting 20-25g carbs,(i know your bootcamp aimed for 50g but i was already a week in and coping fine at 25 and was led to understand this is key to ketosis) around the 80gish mark for protein and around 100gish for fat. My friend calculated my macros and I know that she calculated the protein and fat higher than that but I've still been finding my feet a bit.
We only had a carb target last week as it was a super strict 'get back on the wagon' week! From now on, we don't count. You should be aiming for your daily intake to be high fat/medium protein/low carb - entirely up to you if you want to monitor your macros, but frankly I can't be arsed!
The difficult think about carbohydrate intake is that we all react differently. Some people can tolerate a much higher daily amount than others, and the only way to find out how much you can tolerate is through trial and error.
All of that said, if you lost 10lb in the first 10 days, you were doing something right!