We didn't have the chance to meet Sarah but Jan has been amazing!
He offered to pick us up at the airport and bring us back there at the end of our weekend for very cheap as he told us taxis here are not really honest.
The flat is in perfect location, just by the old town and is really lovely with all you need (towels, shampoo and shower gel, hair dryer, city guides etc)
They created some city guides that they sent us before we arrive with good tips and even a program they advise for 48 hours stay.
We had a really good time and I highly recommend Jan & Sarah's flat.