Thanks! I was going to say the map needed a bit of work around 11-18, but I think it was "good enough". The uncrossable walls probably need to be a bit thicker on the next edition (lots of people punched 18 from above which involved reaching over the top of the wall).
I'm using the Garmin 235 and as Jagge says
these newer wrist GPSs seem to be much less accurate. The worst example is my track from 14 to 15 which is nowhere near like what I actually did (basically straight and down the steps). In fact the GPS track is so bad I'm not even sure which of the two flights of steps I actually went down.