No. 18-19. I went up the same cobbled ginnel as you after I had crossed the main road, but turned and came back. The mapped ginnel was 10m further to the west. I think I was caught out in the same place when I raced here before!
I agree that map is not the best. Too many uncrossable boundaries not mapped. Like you I went low to 17, but only because I remembered it from last time.