Think your where I got stuck at as well
Basically if you got the silver bromide and went to the train station and got the Ray Reflector shard (Speed Demon achievement) then you need to go back to the bell tower im pretty sure (upper left hand corner of your map currently probably, where there is some room to go upward (not the entrance). There should be a reflecting part on the left side of the room that you can use to go higher up. (Basically have you fought the blood boss yet?)
Nope, havent fought that boss. Trying to find this room but all I found was a pathway with spikes. Any chance you can explain it to me like I'm five? 😀 It's in the cathedral, yeah?