The flat had a very overpowering stench of sewerage from my the main bathroom. When we arrived they had hidden it with a strong chlorine smell, but an hour later the smell emerged. We had to keep the door to that bathroom closed throughout our stay but could still smell it somewhat in the adjoining bedroom. At one point the bathroom door flew wide open and I almost threw up from the terrible smell.
Aside from that the internet was very unreliable and would be on and off every few minutes. This was annoying but nowhere near as big a problem as the sewerage smell.
Also there was no soap, no washing up liquid in the kitchen to do the dishes -nothing at all to use during our stay.