Hi
I am not sure if i can help with patios but forecourts and surfaces covered with fuels/oils i most definately can. My company supplies a unique product called FleetKleen which uses a technique called bioremediation to clean, degrease and breakdown hydrocarbons. I have just returned from heathrow today where we cleaned a carpark that some kind person broke into on Monday night and let a deisel tank belonging to a contractor go all over the car park. Our products removed the contaminant, the rainbow effect and leave the surface clean, non-slip/skid, and white again!! If you would like to find out more please contact me and I can send you some pictures and video of recently completed contracts.
regards
darren sharpe