The location and the place itself are both great. The flat is very cosy and comfy. It has everything that you need to spend a few days in the city while having a place like home. The view and the terrace are as described. It is so lovely that we ate our breakfast every day there.
It is about 5 mins walk to the river and 10 mins to the old town for food and drink. The area (Gros) also has lots of great pintxos bars so you don't really need to go far. It is very central for us to access local buses to nearby towns (even took a bus from the stop right downstairs) as well as the coach/train stations to head to Bilbao (9 mins riverside walk).
Patricia is super helpful and flexible, giving us a lot of local recommendations upon our arrival. I'll certainly recommend her place.