Places to eat out in London - for/5:2 dieters/healthy eating mums

I started alternate day fasting and healthy eating this in January and it's going pretty well so far, I've lost a lot of weight and feel so much better. On my non fast days I to eat 'raw' as much as possible, which is fine while I'm at home, but I've found eating out tricky so far. 

I'm going to be visiting family in London tomorrow until Monday and wondered whether anyone knows of any good places that have decent meals for 500kcals or less? I'd rather it be healthy and top end of the cal count than less cals.

I'll be staying near Kings Cross St Pancras so anything close to there would be great.

So, basically it needs to have no: meat, eggs, dairy, fish (or seafood) and not be cooked! Ideally I need meals that are fresh, healthy and full of as much goodness as I can cram in.