Yes, you can spray Dulux Weathershield masonry paint. Below are guidelines for spraying Dulux Weathershield Smooth Masonry Paint.
Conventional Spray: Satisfactory through most equipment.
Thinning: Normal use (not to be exceeded): Add up to 1 part clean water to 2.5 parts paint.
Airless Spray: Typical set up for airless spray application would be a minimum working pressure on paint of 133 bars (2000lb/sq in) with a spray tip size of 0.38mm (15 thou) and a spray tip angle of 65º. Suggested pump capacity is 5 litres/minute minimum.
Thinning: Add up to 1 part clean water to 5 parts paint.