Hello, I hope I can offer some help toward your decision. I do not study Space engineering, but my friends and family have experience in all of these uni's and this field.
Firstly on Cranfield: do not be put off by its size. This is close to my home in Milton Keynes, and despite its fairly remote location to the city, it is pioneering in giving you hands on experience. Our family friend used to own an airfield nearby and taught at this uni and their approach to teaching is so different to the bigger institutions. They are a lot more supportive and the structure of the course is based upon students individually, which is hard in bigger unis. The teaching is systematic but the relationship and rapport you develop along the process with key staff is second to none. You will be amazed at how support networks are put first in all departments here, so doing a tough course like Space Eng will be more achievable. My brother has been doing work experience at Cranfield uni and Air Space since he was 14 years old, in aircraft maintenance and aerospace though. He went every single school holiday and summer until he was 21. His experience was always celebrated by the staff in both offices and he obtained a first class degree from USW, has completed most of his modules for a B Lic. under EASA and now works for Easyjet/ Aeroco. He cites the time at Cranfield as invaluable, despite not being able to offer him a full time role, their support was incredible and they paid him/ appreciated all of his effort.
Surrey: this is a big one. So I did my BA at Surrey in English Lit, but my partner and one of my best friends went on to enter the MSC SPACE ENG after their respective degrees in Mech Eng and Chemistry. I find this department to be very unsupportive. Despite boasting their space centre and pioneering satellite work in the 80s accounts for their success and status, I find this irrelevant. I have not experienced the teaching officially but I have read through lectures and gone through nights where I am planning and helping my partner or friend to find a way to tackle their courseworks. This course is so awfully supported. The pass marks are ridiculous and the examinations are written like the lecturer's are trying to laugh at their students. You cannot complete or work toward your dissertation unless all of your examination and modules are passed which, is very unfair.
It haunts students all summer and if the teaching was better, this could be different. The course sets unrealistic expectations for the information taken on board against, the work load. The material is hard but the structure and support are shambles, so this makes it harder. My partner could not cope with the stress of the degree and so deferred half of the year to complete in the following academic term. When returning to uni, he still struggled. The lecturers give little guidance and little empathy to the nature of this course and the demand. My friend, failed one exam and had to wait all year to resit. He felt the exam resit went badly, which means you are not allowed to resit again, which means he is scared he has failed his entire degree. Surrey's Space Eng dept. will not award you a pass, even if your average is a pass in this case. They are undoubtedly awfully organised and communication is lacking everywhere: from not being able to meet deadlines because the dept. is blind to its own **** ups in submission portals, giving no apology for dept. mistakes or disorganisation. My partner and friend have other colleagues who have failed a number of various exams or modules, whenever I talk about the MSC work with them all, its always negative. Yes, all degrees require you to be meticulous in your learning, but this dept. expect miracles from students. Their extensions for people who suffer from sickness or anxiety are ridiculous too, my friend was only given a day's grace despite medical support citing his high anxiety and stress exhaustion. I think the lecturers could do with a reality check: I appreciate they are experts in their field, but they have no engagement with what it means to be a student again. I have hated seeing what this course has done to my partner and his self-esteem over the last two years. I remember teaching myself what an OBC was just to try and help him with a project.
This however, is not reflective of Surrey. The university is great on average, and many other Eng based depts. priorities student satisfaction and support. I recommend researching this. The uni's overall support system is excellent and their opportunities are great for students. I just feel, watching my partner and various friends go through this Space Eng, course... it has all been horror stories. The course is pretty much all male. But it has broken my heart to see my friends and partner cry endlessly, struggle to talk because of anxiety piling up and continuously feeling like their hard work and determination is thrown aside, because they didn't make a grade percentage. There is no consideration for when things go wrong. This course is intense and it's awful organisation and expectations are half of the issue. I can imagine that if this dept. were to re-structure the course and material into more engaged, hands on, dynamic teaching, the success rate and pass rate would be higher and so to would the student satisfaction.
UCL: I know nothing about this uni first hand. My god brother studied engineering here and was fully supported, listened to and excelled in his degree whilst here. This uni is in the heart of Bloomsbury and is really dynamic, there is so much to do and you won't feel like just a student too, at Surrey you kind of feel that way... that you are "just a student”. UCL is recognised globally and I am sure you can connect with previous alumni. Their responses to prospective students is good [I know this much!] and if you email to politely explain you want to apply but want to find out more from past students and from lecturers, I am sure they will connect you. In fact, I am positive if you explain and approach them, they will invite you for an informal mini open-day to their department if you ask. They really cater to student professional and personal development and so you will find that your network of industry contacts and advisors grows rapidly if you take the initiative.
Anyway, if you want to know more, about Surrey in particular please contact me and I can ask my friend or partner to give you their accounts. It's not been happy or plain sailing here though, sadly.
Good luck.