If they're a trained dietitian then my first instinct would be to say that the advice of people on this forum isn't necessarily much help to you. Generally someone coming on here saying they want to start a very low cal diet would be met with loads of replies saying 'BAD IDEA' but there are circumstances where low cal diets are used (generally after a proper medical examination and dietitian approved though).
This is my personal opinion so don't take this as medical advice but why exactly have they put you on such an extreme diet, if you don't mind me asking? Have you had problems losing weight or have some other medical reason (I have seen low cal diets used to treat type 2 diabetes)? And how long have you been on it? Otherwise I would wonder why you're eating so few calories. I inputted your example menu into MFP and the numbers aren't exact without know the exact quantity of each food you're eating but it came to roughly 800 calories a day and was very very low in carbs and fibre which generally isn't that healthy (again, there are times when this may not be the case). Most people could lose weight eating around 1500 cals and exercising so purely based on the information you've given us, it does seem extreme.
Did your GP recommend this dietitian? If you're doubting whether the diet you're on is healthy then you could always ask for a second opinon. The other thing to consider is how are you going to manage coming off this diet? Obviously that is something you'd work with your dietitian towards when the time comes but staying on low cal diets isn't sustainable.