It should be easy to do a basic camouflage job.
One very important point with motorized dishes is that they will often be at the ends of the arc. That means that you will have to paint the back of the dish if it is light coloured, as it will be clearly seen if viewing from the west or east.
You will also have to paint the mount to make it less visible when the dish is at the ends of the arc. You should Hammerite the mount anyway to protect it (as I have done with my big dish), say Highland Green from the Garden Metal range, or Dark Green from the standard range.
Don't forget to paint the feed arms either, as they will be exposed and will flash in the sun, drawing attention to the dish, especially when it is moving. Many people ruin perfectly good camouflage by leaving the feed arms silver so they glint in the sun.
The fact that the house is 200m away and is actually on a lower level helps a lot, as he would have to look up to see it. That means it wouldn't be in his natural line of sight when in his garden, or when going to the car, etc. This makes life easier. It will be more visible from the first floor windows but the distance and potential shade from the trees will help here.
As the dish faces south, it is facing into the arc of the sun all day, which is just about the worst situation for camouflaging anything!
This is actually one of the advantages of a dish farm, you can put them inches from the ground and often behind bushes or ornamental grasses. But we cannot do without the full arc! That said, if you want to get one of the lower satellites on the arc permanently, then consider a perforated 'mesh' dish ground mounted just behind one of the trees, and painted to be unobtrusive.
When you consider the background, foreground, and slight shade at some angles of the sun, then the colour will have to be averaged to account for very bright sun in summer and the lack of sun in winter, and for low and weak sun in winter.
The best single colour would be a mid brown. The Plasti-kote spray Chocolate Matt should do it. Remember that there is very little green at ground level, so something like Hunter Green would stick out like a sore thumb. The brown should harmonize with the tree trunks, the drive way, the space behind the dish, and the shadows (which will not be deep black due to the direction of the sun and reflected light from the lighter coloured objects around the dish).
If you are going to keep all that drying wood, which would be a convenient wind break, Chocolate Matt would be harmonious with the wood behind and with the maize in front.
This may seem a lot, but it is easier than the 3 to 5 colour version that might be used if there was a lot of greenery at ground level. It would depend on the greenery though, sometimes a simple pattern could be used.
I think that the one solid colour may be fine here. When it is up and has been painted you could look at it from a distance and decide if it needs a pattern applied to make it fade further into the surroundings. This would probably involve using a brush and e.g. Palsti-kote fast dry enamel Flat Black. It would need to be in place to decide what pattern would be best.
Chocolate Matt would also be a good compromise for the back. Cappuccino Stain is a possibility if you remove the wood and want a lighter brown colour so the area does not seem so dark. You might decide that you prefer Everglade Satin green or Dusty Jade Matt or the brighter April Green if you can see the back from the house and prefer green to brown. Green is a more cheerful colour, especially in winter.
There is often no need to cover the back totally, you can spray at a distance which means it covers more area with dots, and some of the dish colour will remain as small dots. If you step back 15 yards you will no longer see the dots of original dish colour, the new colour will appear solid. This can save money on paint.
It doesn't really work on bright white dishes, sadly, so in that case you have to paint it properly.
Avoid gloss paint. Satin should be fine as dishes have a satin powder polyester coat to protect them from the elements and airborne contaminants. The exception is the back of the dish and the mount, if they are mostly in shadow.
You might consider planting a few pollarded mini trees or perhaps some small evergreen bushes, the same height as the maize, right in front of the mans house when looking from the dish. These do not have to be touching like a wall. They can be a few feet apart because the distance and angle of view means they will appear to be close together when viewed from their house, and the brown colour of the dish will make it appear shadowy, if it can be clearly seen at all.
The barn will be plenty big enough, I'm sure the three goats, two geese and lone duck can make space for you. My only worry would be the smell, but I'm sure the animals wouldn't mind. 
