My experience was similar if somewhat more organised - multiple interviews over an extended period of time, before a trip to their office where no one seemed to realise I was there to be interviewed.

I ended up having lunch with the HR person, who was fairly scathing about the whole thing.

Got an offer - which looked fine, until I realised they had me down to work in another city despite all conversations being about working at the site and with the team closest to me.