Not being rude here, so please take this with a pinch of salt.
If you are offering caravan washing, solar panel washing, jet washing as well as window cleaning. You are going to get "every little"; in the sense that you wont have much work that is regular and profitable. I know a guy who does pressure washing, window cleaning, hedge cutting, wall painting, lawn cutting....the list goes on. He is a nice guy, and has customers who are happy to use him, but he doesn't exactly excel at one thing; and always seems to be a bit low on work, so to counteract that he will do extra jobs that people ask him to do that he doesn't already do and add it to the list of things he already "does".
The point i am making here is that you can be too many things to too many people. In my opinion you should concentrate on one or two things, and really excel at them and work it so it becomes very profitable or you risk losing focus on what it is you are trying to achieve from your business.
So if its caravan cleaning, window cleaning, patio driveway cleaning...whatever it may be try to take the "core" business you want to focus on the most and build on that. You don't want to end up a jack of all trades, and trust me you could if you don't keep your focus in check.