I reckon it is just a feature of the building, a bloody ugly one but..
If you know the address look on street maps and see if the next ones along are the same, one in one out all the way along the row.
The gutters are in alignment.
... a house hear the top of the terrace looks like it's had a new front wall.
...
The gutter on the RHS is slightly mis-aligned
You mean the left in the photo?
It looks like a drop, or maybe a stop-end. Normally gutters only service a couple of houses because of down pipe flow limits.