I'd be really surprised if you don't have at least one altnet in an apartment building, Hyperoptic is pretty common in London.

I've got access to 4 seperate FTTH providers now in my apartment (all using different infrastructure, not including resellers): VM, Openreach (BT) FTTP, Hyperoptic and now Community fibre.

The limiting factor on speed now is WiFi, which cannot manage 1gig even closer to the router.