Thanks for replies, the job I quoted today will I think be possible with wfp without to much hassle so if he accepts that's the way I will go on this one, I'm sure some would be more suited to a pressure washer though so that's something else to invest in I think.
Only trouble is the house I quoted for was large detached and I quoted £30 for the windows and he thought that was for the rest as well, his jaw dropped when I told him £100 for the rest.