Hello Raibeart,
Just wondering if you managed to remove your chimney breast in the loft as part of your loft conversion.
Did the structural plans get approved by building control?
I am also in a similar situation (1930s 3 bed semi detached) and in process of getting planning approval and building regulations for a hip to gable loft conversion. I too would like to remove the chimney breast in the loft but not sure if it is feasible or even allowed.