Posted: 07/05/2014 at 10:19
To me it looks a bit of a mess. The black spot is back, and it needs to be pruned back hard to rectify the shape. As black spot is a fungal disease, hygiene is critical, so cutting out the affected stems and burning them will be necessary.
You need to create an open bowl shape when pruning so prune to outward facing buds only.
When you treat for black spot, use a watering can as the fungal spores will persist in the soil. I can't figure out how much airflow around the plant you have, it looks to be stuck in a corner and that won't help it.
Pruning now won't hurt it, and after the black spot treatment mulch with FYM or good garden compost.
Let it go for a few months and see how it goes after that. I think it's position and the airflow around it is the root cause, the fungal spores will gather and persist if the airflow is bad.
If it doesn't improve, then I'd move it to increase the airflow and start again.