Seems to me a curved facade — especially in a place like Brighton where you have eater views — may simply be a choice made to "show more coast" to a potential homeowner. Maybe that's also what the original builder had in mind... given the age of the house, I imagine it was built specifically for someone.
Could be @denmarkguy but I wonder why others didn't do the same. 😁
I'm not sure if it was built specifically. Most of the research I've done says that the buildings were built by developers in whole terraces or crescents etc. This one might well be different though.