Hi
Marshalls Heritage is a top quality product - Its price will be about £28 plus vat in a builders merchants but your man will get 30% off that price (which he'll keep for himself no doubt)
If you want a good product at a cheaper price have a look at www.brett.co.uk - Canterbury range...
No chemicals should be necessary if your pressure washer is up to the task. Don't just think PSI, think PSI X litres per minute of flow. Always point the lance away from you at and at an agle of 30 degrees. Keep the tip of the nozzle a couple of inches away from the surface being cleaned (you...