If your daughter is definitely set on sustainable development and a related career, then the opportunities SOAS can offer her are probably unmatched by the other institutions, simply because SOAS is so very specialised.
However, if she is just sort of interested in sustainable development and doing it because she needs to do a degree in something then she may be better choosing St Andrews or Edinburgh for exactly the same reason.
In terms of student life and reputation, although they are all very good institutions academically, they are very, very different places.
SOAS is a small institution in a very big city. Its students tend to be very political, quite diverse and it has a larger population of mature students and international students than average. Back in the ancient past when I studied there, there was actually a fairly large public school contingent, but they were very left-wing posh - lots of sixth form Marxists in keffiyehs. A lot of the intercollegiate halls are nearby, so you can save money on travel in the first year, but although I think international students get priority in some halls post-first year, you would be unlikely to get a place for all three years and private renting is very expensive.
St Andrews is completely different to SOAS. It's in a small, quite isolated town which is dominated by students. It has a reputation for being traditional Tory posh because it attracts a lot of English students from traditional public schools, minor royalty, etc., due to its good academic reputation, old buildings and so on. Some people find the hooray henry element to be rather dominating and isolating, others don't. It has had a very large population of American students ever since Prince William went there.
Edinburgh is kind of in between. It's in a big city, but not as big or as expensive as London and it's a bigger institution generally, so less dominated by any particular type of student. If your daughter's main wish is to experience city life, then Edinburgh could be a good compromise.