John Merrill did it clockwise as well. According to him going anti-clockwise was the devil's way. I think he was quite spiritual as he started and finished at St Paul's Cathedral, and if I recall correctly he met the lady who was to become his wife (Sheila?)in Scotland whilst recovering from a stress fracture.
Barcelona is a long way from St Sebastian and the GR11 doesn't go there. Easiest part of the section is from Hondarribia through Navarra. Nicest part is near Ordesa - a long way from either Barcelona or St Sebastian.