Power washer

I use step ladders. Have to careful they don't bang into the side of the van [some people pad the ladder edge]. Usual health & safety concerns apply for working at height! Then I use a long reach brush from all four sides. This means some parts get cleaned twice. I have a short handled soft brush for going around roof lights, the TV aerial and guttering.

My choice of cleaner is BioPro's CaraPac wash n wax. Sometimes I additionally wax the roof with Autoglym using the long handles pole with microfibre cloths covering the brush end. There are numerous products available and all make claims which may or may not be true. CaraPac works for me and BioPro say the product is environmentally friendly. Not easy to get hold of though.

I use a telescopic ladder to give access to clean the roof (Santa is not too far away if you haven't got one) but the French have the right idea to help MH owners .....

You wouldn't give a chainsaw to six year old (nor should you use one yourself without proper training and protective equipment) but used correctly they are immensely useful. 

Likewise a power washer is very useful for cleaning your M/H and I do use one.

However the potential to remove mastic seals decals or even paint is real if you use high pressure especially if the nozzle is close. You pressure wash kit should have come with a variable pressure lance (if it didn't you can probably buy one as an accessory) and if you set this to a gentle pressure it is very useful for washing down.

I mainly use my jet-wash to cleaning mud off wheel arches and mud-flaps (medium pressure  used carefully). Additionally with a professional snow foam dispenser the pressure is very low and speed of application fast as the vehicle is foamed using a wide arc. After leaving for a few minutes the foam is removed using the lowest pressure setting. Very simple and very effective and something you can do in winter when you wouldn't spend hours doing a bucket and sponge job. 

I never use commercial jet-washing (coin-op or manual operator) because you have no control over the pressure settings on the equipment. 

So in my view jet-washes have their place but must be used with care and respect. 

My van is 8m long. I use top of range domestic karcher. I ensure pressured water is at least 2ft from vehicle. Wash down first then snow foam them soft karcher brush then rinse. I rest ladder against van with towel around top of ladder so no scratch marks. Keep water away from exterior fridge vents. Always comes up a treat. Bring your van to wiltshire....I'll clean it for you! 

Thanks again everyone, really like the photo from France, perfect!