Went to address on website, found an empty office, asked a guy outside if he had heard of the apartments and got lucky he was the manager! He took us two streets away to an apartment in a private building.
Apartment was old but functional and clean, close to shops etc.
Didn't have my phone with me, later found messages he had been ringing me to say I only had a limited time to check in - nothing if any of this mentioned on website.
Seems this is a company that rents out selective private apartments in the area, which is fine, but they need to have someone at the office, or at the very least a sign at the office telling you it is the correct place and please phone the manager for check in.