Great location, wonderfully well appointed flat, grocery & other stores immediately near by, & communication with owner was great. We ran into an issue with one of the showers & the owner took care of it right away.
There is a pub just outside the window of the second small bedroom that can get quite loud & a lot of cigarette smoke wafts up - caution if you like to sleep with the windows open.
As with many flats in old European center buildings, there is occasionally a sewer gas smell that comes from the bathroom. If it is summer, open the window slightly & it is okay.
I would stay in this flat again when coming to Bilbao.