Social life is what you make of it. You can find (or avoid) social life at any uni. Especially for one in London, where there is so much available to do - it's completely down to you how involved in that you get.
As for the uni, I was not in that department while there so can't comment on it specifically, but in my area the lecturers were absolutely fantastic, incredibly dedicated, always so happy to be teaching and sharing what they know and just so invested in the teaching of degree students (which is not always a given in universities). So on that front I had an excellent experience and it was really formative for me, and I'm deeply indebted to my lecturers and have a huge amount of respect and gratitude for them.
However the admin is terrible there. Just absolutely awful - I know a lot of students on TSR complain about uni admin processes and procedures and timelines, but I've been at multiple universities as a student and worked at another as a non-academic staff member and SOAS was bar none flat out the worst. So this is not a spurious comment, I've got a fair bit of comparative perspective there.
It's a real shame as it completely tarnishes the otherwise fantastic work the lecturers are doing. I will contend I don't necessarily think this is out of malice or ineptitude on the part of the admin staff (at least not necessarily...the latter perhaps a touch at times...) but simply that their administration is run by a skeleton staff and there simply aren't enough people to deal with it (which causes delays and worse, errors, largely due to things having to be cross covered by non-specialists whenever one person is on annual leave or off sick). That said if you don't need to engage with the admin staff for any reason (which I didn't for a fair bit of the course to be fair) it's a non-issue. It's just very frustrating as usually if you need the admin side of the uni to do something for you, it's usually something urgent or that makes a significant financial difference to you personally.