I arrived at the guesthouse on time and had no problem with the check-in. The place is quite basic but clean and comfortable. The center of Porto is about 25-30 min walking distance. Currently, breakfast is not included due to COVID.
In my trip, there was an issue with the front door that kept me out of the guesthouse for about 2 hours at night (22-00). However, the response from the owner was relatively fast and I got reimburse for the problem.