These are listed in the brochure - 105 sq m pitches, three times the 'normal' pitch size (and price!!).
They are probably the result, as on MB last year, of when they mark out the pitches. They would lose too much space to leave an 'access road' to all regular pitches, so they just double or treble-up. It is most likely that these will be at the edge of the site, ie up against the perimeter fence or the road.
Del