Knockdown is easy to duplicate ... try the technique on some scraps of cardboard first. Dilute some drywall mud until it is the texture of sour cream - holds a nice peak. NEED: drywall mud, big coarse sponge, WIDE (10in or larger) drywall blade, clean cloth. Spread a bit of the compound onto a damp coarse sponge. Dab it on the wall where you need texture in an irregular pattern - repeat until the area is covered with peaks of mud alternating with some open areas. When the peaks are stiffening, but not dry (stiff pie dough texture), draw the drywall blade across the patch in one quick scrape. Hold the knife at about a 45-degree angle. Knock the peaks down! Wipe the blade clean between scrapes. The harder you push the blade against the wall the thinner and flatter the knockdown will be. Let it dry, prime it with drywall primer, and paint it. IMPORTANT: Overlap into the already textured area by a foot or more, fading out erratically, and even create some random clouds of new texture. You need to break up the outline of the bald spot.

If you have ridges you have to sand them down to get rid of them. Are you sure that the guy didn't use a spray texture on the walls prior to painting. It hides many imperfections. Is it an actual orange peel texture? If so you can buy a can and spray it on the flat areas to get that dimpled effect. Test spray on something else to see how far away and how heavy to spray. I used an artist brush to knock down overly large goobers that the orange peel spray sometimes left behind. Poor technique can cause dimpling - letting the roller get too dry and being forced to use excessive pressure can cause dimpling. This can also leave ridges. If you share a picture of the textured and non textured surfaces we will be better equipped to help.

''Any idea why it came out so light for them?" Yup,me tinks they went to the paint store and chose a color as b0est they could from memory and naturally they missed it by a mile. "And what can I do to paint that spot to match the colour?" If you are pretty sure the room was origionally painted with Behr Ethiopia,buy a gallon and try it. If the match is much better but still a little off,"feather" it out. If you are still not satisfied,paint the one wall with the new gallon and it will look fine. Another option is to make that an accent wall painted a complimentary color( yellow tint) .

check out number 5 & 8 https://www.thehomeroute.com/11-different-types-of-ceiling-textures-for-your-home/ You can come close without a roller I had the swirl in a bathroom. I went over it with wall paper liner Not something you can do for a ceiling as my space was much smaller.