Yep I go crown oil as well, but Taybur have just beat his price on Kero so I'm going to ask about red next time. May be worth you asking if you want a better price.
Crown are dearest mate. You still need some red in with your kero. Don't just burn kero it's not lubricated enough therefore your fuel pump can seize.
Only use Kero in the Karcher (yes I own a Karcher) used for trailer washing on Tuesdays by someone who works for me.
I add some oil that the tech at Karcher recommended , only a few drops and I've not had it seize yet in ten years so it must work. Not ideal I know and probably does damage them. Don't think I'd do it in the diesel ones but works ok in the 240v Karcher.
Asked him about the Falch the other day as well and he can do repairs if you ever need his number.