PeteCrighton I would want to install on Uberspace, which wouldn’t be sufficient to run Discourse, for example.
I'm using Uberspace myself and have successfully installed flarum with them. I'm on a budget right now (5 Euro per month) and flarum is doing just fine. Although I have to admit, that until now there are only two users testing my flarum installation, so I can't tell how things will turn out when the number of concurrent users increase.
But if Discourse has higher requirements already with a basic install, I would suspect that flarum will continue to be lighter on ressources even when the number of concurrent users go up.