Hi Fraser,
There are jobs for non-Swedish speaking within tech in Gbg, however, most employers would prefer you to at least show an honest willingness to learn Swedish. I think the reason for this is the Swedish informal corporate culture, decisions often being informally made (in Swedish) over a coffee rather than in a formal meeting (where English would be used).
Let me know if you need any support in your job search, I co-founded a tech-recruitment firm in Gbg some years ago and still have contact with the ones running it. If so - send me an email at fredrik.cj@gmail.com.