Met up with them in their office opposite the Prague Main Train Station and they provided an information sheet with tips for the both the city and the most convenient places for food/money changing around our flat.
The flat was a 20 minute walk from the train station or a short 5 minute tram ride away from the station. We loved the very modern flat with all the amenities that one will ever need. There are 4 keys to get through before you enter the flat so you should feel quite safe once you're in. There are lifts available but for some reason the lifts are at every half floors along the staircase, so one still needs to walk with luggages for half a floor, so one should keep that in mind if that is a problem for you.
The location of the flat is pretty central, we ended up walking through the old city about 15 minutes walk away everyday we were here so if you're alright with walking one can literally cover all the sights in Prague without taking transport.
All in all, pretty satisfied with the flat.